


Possession

by just_a_winchester



Category: Shadowhunters (TV)
Genre: Action/Adventure, Angst, Blood and Gore, Canon-Typical Violence, Dark, Demons, Deviates From Canon, Drama, Dreams and Nightmares, Emotional Hurt/Comfort, F/M, Fluff, Hallucinations, Hurt Alec, Hurt/Comfort, Illnesses, Love, M/M, Pain, Possession, Some Humor, Trauma, Violence, Whump, please don't hate me for hurting Alec
Language: English
Status: In-Progress
Published: 2018-02-08
Updated: 2018-03-24
Packaged: 2019-03-15 11:07:51
Rating: Not Rated
Warnings: Graphic Depictions Of Violence
Chapters: 11
Words: 28,266
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13612074
Author URL: https://archiveofourown.org/users/just_a_winchester/pseuds/just_a_winchester
Summary: Alec gets possessed by a demon. The Shadowhunter crew have to find a way to save their friend before all hell breaks loose and a Greater Demon wreaks havoc on New York City.





	1. Tongue in Cheek

The man in red headed quickly down the street, his huge boots pounding on the pavement like a drumbeat. His head was shaved, black vine tattoos circling his skull. He flicked the cigarette he'd been smoking onto the ground and turned left, down an alleyway. He glanced over his shoulder as he turned, and for a second his eyes flashed green in the sunlight. No one would have noticed it unless they had been looking closely.

Alec had been watching intently. 

He'd been trailing the demon for the better part of a day - a werewolf in lower Manhattan had tipped off the Institute about a strange creature spotted in one of the Downworlder bars, a creature dressed in red that didn't look entirely human, nor entirely Downworlder. Alec had originally thought it was a demon was possessing a human, but he'd never seen a possession cause someone to have eyes like that - green and glowing, as though there was a force or an energy living behind them. The edges of the demon's body shimmered and shifted as he moved, never entirely solid, as though he were being held in at the seams. Alec had never seen anything like it, not in any of the records they had at the Institute. Or at least in any that he'd read.

The demon had run him all over the city, stopping at Downworlder herb stores, antique stores, speaking to vampires and werewolves in shadowy alleyways and street corners. The demon was looking for something, but Alec had no clue what it could be.

He cut across the street and followed the demon down the alleyway, weaving around pedestrians. It was as seedy as any alley in New York city - dumpsters, graffiti, trash. It ended in another alleyway that crossed it, forming a T. Alec crept carefully down the alley, his bow at the ready, his eyes darting all over the place, searching. There was nowhere for the demon to hide, but he was gone. 

Alec reached the end of the alley and peered around the corner, looking both ways, his heart pounding with the anticipation of a fight.

Nothing.

He stood, his shoulder slumping. All that work, and the damned thing had given him the slip. He ran a hand through his hair and swore under his breath.

'Now, now. There's no need for that kind of language.'

The gravelly voice was coming from right behind him, and Alec nearly shot out of his skin. He spun, raising his bow, but the alley was empty. His heart was racing, and he turned, looking down all three alleys, but there was no one around. 

'Oh, sorry. Did I scare you?'

Alec looked to his left, lifting his bow. The demon was sitting on the corner of a dumpster, his elbow on his knee, his hand propping up his chin. He smiled at Alec with long fangs, his green eyes glowing. 

Alec drew back the bowstring and was about to fire when the demon tutted.

'I wouldn't do that if I were you,' the demon admonished. Alec ignored it and let the arrow fly. It hit the wall behind the dumpster, breaking into pieces with a loud clatter. The demon had disappeared in a puff of red vapour.

Alec reached hurriedly for another arrow, but as he went to nock one a hand reached out and grasped his bow tightly. He looked up to see the demon standing in front of him, grinning. 

'Let's not try that again,' the demon said.

Before Alec could react, the demon slammed a hand into his chest, and Alec flew backwards, his bow ripped from his grasp. He hit a wall with a thud, his head slamming back into the wall with a crack. His vision blurred black at the edges as he fell to the ground on his side. He lifted his head weakly, looking blearily at the demon, who was approaching him from across the alley. Alec rolled and pushed himself up so he sitting against the wall, his head throbbing, and fumbled for the seraph blade strapped to his thigh. 

The demon tossed the bow aside and crouched in front of Alec. 'Did you really think I wouldn't notice you following me?' the demon growled. He lifted a hand and inspected the talons that grew instead of fingernails. 'I thought it was cute at first, but then it just got annoying.' The demon raked his eyes up and down Alec's body, a look of disgust on his face. 'You Shadowhunters. Always meddling in things. Your kind are nothing but-'

The demon's words turned into a choked groan. He looked down to see Alec's seraph blade protruding from his chest. The demon let out a rattling moan of anguish and then disappeared in a red cloud, reappearing a few feet from Alec. The demon stared down at the sword sticking out of him in shock, his hands pressed to his chest as green blood poured out of the wound and spilled down the demon's clothing.

Alec felt a glow of triumph that quickly turned to confusion when the demon didn't turn to ash. He watched with growing horror as the demon wrapped his hands around the hilt of the blade and tugged. With a horrible squelching sound, the demon yanked the sword from his stomach, leaving behind a jagged wound in the middle of his chest.

The demon dropped the sword with a clang, his arms spread wide as if in supplication. Red smoke seemed to surge off the demon's body, but the demon didn't disappear this time. Instead, the smoke circled the demon and entered the wound, knitting the sides of the wound back together until it was solid flesh, and then the demon's clothes became whole again. The smoke dissipated, and the demon cracked his neck before fixing Alec with a look of rage.

Alec heard a little voice inside of him say ' _of course the demon can heal itself, how stupid of you'_ when the demon disappeared again. He reappeared right in front of Alec, crouching over his legs, fangs bared. A hand flew out and grabbed Alec around the throat and he choked. The demon stood, lifting Alec with him and slamming him back into the wall. For a moment, Alec was dazed, and then he reached up for the hand cutting off his air supply, scrabbling weakly at the demon's hand.

'I just don't understand the nerve of you people,' the demon was saying, barely noticing Alec's attempts to free himself. 'First, you follow me on my private business, and then you attack me unprovoked. And _then_ , you stab me! It's honestly just...rude!' The demon squeezed Alec's neck tighter, and Alec's arms dropped. He could see white spots in front of his eyes.

'I was going to kill you quickly, you know,' the demon hissed. 'Make it "quick and painless", as they say. But I think I have a better idea for you, Shadowhunter.'

The demon leaned in close to Alec, sniffing along his jawline, and Alec cringed, unable to wriggle away from the close proximity. The demon smiled slightly, his fangs poking through his lips. 'Yes, I know exactly how to make your death...interesting.'

Alec felt a jolt of fear at the demon's words. He tried to push the demon off but it was no use. There was no escape.

The demon opened his mouth, and then it kept going, opening and opening, until Alec was staring into a black hole. His brain struggled to comprehend the impossibility of what he was seeing, but he couldn't breathe and his head was spinning and it was so hard to move, so hard to think straight.

There was something climbing out of the demon's maw, something black and disgusting and not quite ethereal. Alec let out a choked cry as the thing moved quickly up the demon's throat, sliding almost effortlessly over the black surface, until it reached the demon's mouth. The black creature scrambled up the demon's arm until it it reached Alec's chin. He let out a moan of disgust when he felt the thing slide over his lips and approach his nose. He felt the smoke enter his nostrils and burn in the back of throat, and he gagged. 

His heart was beating so quickly it felt like it would burst through his chest. He couldn't breathe. He wanted to shout; he wanted to throw up. He wanted to claw down his throat and pull the creature out of him. His vision was flashing colours, white and black cascading until his body gave in to the panic and lack of oxygen, and he passed out. He slumped, his chest and throat and mouth and head burning and throbbing with pain, and then there was nothing but the void of unconsciousness.

The demon let him go and he fell to the ground in a heap.

The demon grinned, red smoke enveloping his body, his last words echoing over Alec's lifeless body. 'Have fun, Shadowhunter...'

* * *

 

Alec opened his eyes to see Jace hovering above him.

'Alec? Alec, damn it, wake up!'

Alec blinked. It was dark. He was in an alleyway. His head hurt. 'Jace?' he mumbled, pushing himself upright. His head spun. He felt like he was going to be sick. 

'Oh, thank the Angel. You okay?'

He wasn't, but he couldn't quite explain that to Jace. He didn't really have to, anyway - he knew Jace could feel where it hurt. 'I don't...where are we?' His throat burned when he spoke, and he coughed, lifting a hand to his neck. His skin ached when he touched it, and he realised he had bruises around his throat. 

'Brooklyn. I came looking for you when you didn't check in,' Jace said. He reached over and forcefully, but gently, pulled one of Alec's eyes open, staring at the pupil. 'You've got a concussion, I'd bet,' Jace said. He let Alec's face go, who moaned as the ground tipped underneath him. Alec leaned his head back against the wall, praying to the Angel the world would stay still long enough for him to catch his breath, organise his thoughts.

'What the hell happened?' Jace asked. 'I thought you were supposed to be working a lead, not getting yourself beaten to a pulp.' Jace's voice rang with worry, and that only made Alec more concerned for himself. He must look a sad sight for Jace to be this worried about him. 

Alec frowned. It hurt to think, hurt to move. He tried to remember how he'd gotten there - _alleyway, alleyway, why was he in an alleyway?_ \- but he couldn't. His memories were fuzzy and his brain was slow. Probably the concussion. 

'I don't know.' Alec looked up at Jace, and fear flashed through him, the only thing coherent to him, that made sense. 'Jace...I don't remember.'


	2. Probably Nothing

**Summary for the Chapter:**

> Alec doesn't remember what happened to him in the alley, but he knows something isn't right.
> 
> (Warning: this chapter contains mentions of throwing up and blood. Don't read under the line break if that shit ain't up your alley).

Alec winced as Isabelle pressed her fingers into the cut on his head. 

'And you have no idea what did this to you?' Isabelle asked. 

Alec closed his eyes and sighed. 'Izzy, I'm telling you, I can't remember anything.' Alec jumped as Isabelle's fingers brushed over a particularly sore spot.

'Well, I'd say that's probably due to a concussion, but I'm no doctor.'

'Yeah, I can tell - are you done yet?' he asked irritably. She sighed and stepped back off the infirmary bed, where she had been kneeling to inspect Alec's wound. His  _iratze_ rune was already working - he could feel the other bruises and scrapes on his body healing - but head wounds were tricky. 

'A "thank you" would be appreciated, you know,' Izzy muttered, pulling her latex gloves off with a series of snaps.

'Yeah, thanks, Iz,' Alec mumbled. He leaned forward with his elbows on his knees, his forehead pressed into the balls of his thumbs. His head was throbbing, but thankfully the dizziness had subsided a little. He just hoped the pain would ease soon as well.

'What's the last thing you remember?' Jace asked.

Alec squeezed his eyes shut, trying to think back to earlier in the day. He'd gotten the tip-off, something about a strange demon. He'd collected his weapons...and then there was a gap, like his head was filled with static. 

'This morning...and then nothing.' Alec let out a noise of frustration. He straightened, blinking wearily in the bright lights of the infirmary. Jace was sitting on the bed across from him, following his movements closely, as though he was afraid Alec would disappear if he looked away.

'Is that normal?' Jace asked Isabelle.

She shrugged. 'Memory loss is common with head injuries.'

'Izzy's probably right,' Alec said. He let out a shaky breath, and then stood slowly. The room spun for a moment before settling, but his head continued to throb sharply now he was standing up. He paused, then headed for the door of the infirmary, his feet dragging on the floor. He felt like a zombie, barely able to remain upright, his eyelids weighed down, his mouth dry.

'Where are you going?' Isabelle called after him.

He was walking like he was drunk, one hand held out to steady himself. God, this sucked. 'Gonna lie down,' he mumbled. 

'There's a perfectly good bed right here,' Isabelle replied. Alec ignored her - he had no intention of staying in the infirmary overnight, with the bright lights and the people checking on him constantly and the hospital smell. He was perfectly capable of sleeping in his own bed. He reached the door and swung it open, grunting a little at the effort. It was pathetic that a bump on the head could do this to him. 

'I'll come see you later,' Jace called after him. Alec waved a hand in response and turned down the hall, thinking only of sleep.

Getting to his room was harder than he'd thought - he occasionally had to stop when the pain became too much, his head aching like it had been hit by a bus - not that he knew what that felt like. He was grateful the Institute was quiet at this time of night, the halls pretty much deserted. He didn't particularly want people to see him like this. 

He made it to his room and sank onto the bed with a happy sigh, the mattress squeaking under his weight. He pressed his hand into his forehead again, rubbing at his skull in the hopes that would relieve the aching. He wished he could remember what happened - a whole day of his life was gone, blurring into nothing. He frowned, trying to push past the static in his head, trying to think...

Blurry images flashed through his brain, incoherent moments. _A flash of red. The smell of New York streets. A hand around his throat._

There was a knock at the door. He looked up sharply and immediately regretted the movement, wincing. Magnus was standing in the doorway, his hair flyaway, his eyes shadowed. 

'Magnus. Hey.' Alec felt a surge of guilt - he'd intended to call Magnus, but there had been so much going on that he'd forgotten. He figured a concussion was a reasonable excuse.

Magnus approached the bed and sat beside Alec, the mattress sinking inwards with their combined weight, their shoulders touching slightly. 'Isabelle rang me,' Magnus explained. He sounded out of breath, as though he'd been running.

Alec sighed. 'I'm sorry I didn't call you myself.'

'That's quite alright...Alexander, are you alright?'

Alec squeezed his eyes shut. 'I'm fine,' he said, but his voice was strained, unable to hide the pain.

Magnus hesitated. 'You don't sound fine. You certainly don't look fine.'

Alec laughed gently without humour. 'Thanks.'

'What happened?' Magnus reached over and took one of Alec's hands in his own, rubbing small circles into Alec's palm with his thumb.

'I don't know.' Alec dropped his head onto Magnus's shoulder. 'I remember getting ready to leave the Institute this morning. Next thing I know, Jace found me on the ground and brought me back here.' His hand balled into a fist, his knuckles pressing uncomfortably into his head. 'It's so strange. I hate that I can't remember anything.'

Magnus was quiet for a moment, his thumb still drawing circles in Alec's palm. '...you got hit on the head, right? I'd hazard a guess that's why you can't remember anything.'

'That's what everybody keeps saying,' Alec grumbled.

'But...?'

'I can't help but feel like something's missing. Like something's wrong.'

Alec felt a hand reach up and gently rub the back of his neck, and he closed his eyes at Magnus's touch, the massage easing some of the tension in his neck and head. He wondered if Magnus was using his magic to ease the pain.

'You should rest,' Magnus suggested. 'Things will make more sense after a good night's sleep.'

Alec hummed in response, his frustration draining away at the thought of sleep. He was so tired...

Magnus helped him take his shoes and pants off and then Alec dropped onto the bed like a stone, his aching body groaning in protest as he lay down. He closed his eyes, sleep already creeping up on him like the first frost of winter. 

'Magnus?' he mumbled out, unable to open his eyes. The warlock was sitting on his bed, watching him fall asleep, his hand resting on Alec's leg.

'Yes?'

'Will you stay with me?' Alec knew the words were slurred. He Magnus understood what he'd said, because he was too tired to repeat himself.

'Of course I will.'

'...in the bed?'

There was a brief pause and then Alec felt the weight on the bed shift. The blanket rustled and rose, and then a hand was wrapping around his chest, holding him close. Magnus's breath was warm on the back of his neck, tickling his hair and skin.

'Of course.'

* * *

 

Alec woke some time later in the night, his stomach churning. Magnus was curled against his back, his hand draped over Alec's hip. Alec smiled at the feeling of being held, happy Magnus was here with him. A tiny part of him dreaded to think what could have happened if his parents had walked in on them like this, but then he tossed the thought out of his mind. It didn't matter what they thought, so long as Magnus was with him.

He lay in the dark, staring blankly at the wall opposite him, trying to persuade himself to go back to sleep. His headache had gotten worse, if anything; the pain behind his eyes was piercing and harsh. He would have to go back to the infirmary tomorrow and see if they had any mundane medicine for pain, because the _iratze_ clearly wasn’t helping very much.

His stomach lurched again, urging him to get to the bathroom. He sat up as quickly as he could, the dizziness making him feel sicker. He got to his feet and his stomach almost inverted itself with the change in position. He staggered quickly to the bathroom, shutting the door behind him and making it just in time to throw up into the toilet.

He sat on the floor when he was done, his stomach heaving, empty but still roiling. He was exhausted, the effort of retching making his limbs shake and his throat ache. His head pounded heavily with every beat of his heart. He wiped his mouth with the back of his hand and as he lowered it, he caught a flash of colour out of the corner of his eye. He looked down at his hand and the breath caught in his throat. 

Blood was smeared across the back of his hand. Alec froze, staring down at his hand as though he'd never seen it, or blood, before. He hesitantly touched his lips with his fingers and they came away red and dark. He pulled himself onto his knees, forgetting the pain in his head, and peered slowly over the edge of toilet bowl. The inside was covered with blood as well, viscous and dark. He wanted to throw up again at the sight of it.

_What was happening to him?_

'Alec?' 

He flung himself into action at Magnus's voice, reaching up to flush the toilet, but he was too slow. Magnus opened the door and stared down at the toilet. Alec froze, petrified, expecting Magnus to freak out. Magnus didn't say anything. His eyes skipped past the mess and landed on Alec, creasing with concern.

'You okay?' Magnus asked, and it was like he hadn't even noticed the blood, the red. Alec stared at him, confused, and glanced back at the toilet. His stomach jolted in surprise - the blood was gone, replaced with standard stomach contents. He lifted his hand. No blood there either. 

He swallowed thickly, his mind racing. Could concussions make you see things that weren't real?

'Alec?'

His head snapped up towards Magnus, who was still watching him with worry.

'Yeah, I...yeah,' Alec said absently. He used the sink to haul himself to his feet. His hand shook as he flushed the toilet, watching the water churn, clear of any sign of blood. He turned to the sink, washing his hands under the tap.  _Blood...he'd seen blood...why had he seen blood?_

'You alright?'

Alec had almost forgotten Magnus was still standing in the doorway. He realised he was probably freaking Magnus out. He nodded slowly, the water still running over his hands. 'Yeah, I'm okay.'

He turned off the tap and glanced up in the mirror. He let out an audible gasp. For a split-second, he didn't recognise his own face.

His reflection was pale and sickly, the eyes dark and hollow. He looked thin, his cheekbones jutting out of his face, his cheeks almost concave. His lips were chapped, and a thin trail of blood ran down his cheek from the corner of one of his eyes. 

Alec blinked, and the horrible reflection was gone, replaced with his normal face, his human face. He looked a little peaky and pale, but at least he looked alive. 

'What is it?' Magnus asked. 

Alec shook his head, his eyes trained on his reflection waiting to see if it would change again. It didn't, even when he blinked slowly. 'Nothing.'

The pain in his head was returning in full force, but his eyes were wide and his heart was racing. He felt both exhausted and completely awake at the same time, his brain wired. 

Magnus didn't push him. 'Come on,' he said gently, placing a hand on Alec's back. 'Come back to bed.'

Alec allowed himself to be pulled away from the bathroom, unwillingly tearing his eyes away from the mirror. He glanced back at the toilet as he passed, and he could have sworn he saw a flash of red before Magnus closed the door behind them. 

**Notes for the Chapter:**

> Hello! Thank you all so much for reading, I didn't think this would get this response so quickly, so here's another chapter! I hope to update this ASAP, but you know how it goes. Please leave a comment if you have any feedback, and I hope to see you again soon!  
> \- jaw xx


	3. Detective

**Summary for the Chapter:**

> Jace investigates the demon Alec was tracking.

The alleyway looked as much the same as it had been when Jace had first seen it - trash everywhere, a dumpster pushed against one of the brick walls. The only thing out of the ordinary were the bloodstains on the ground, green splatters spreading across a distance of a few feet in the middle of the alley. 

Jace crouched by the largest stain now. It was about a foot in diameter, dried into the pavement. This was from where Jace had retrieved Alec's seraph blade and bow. He hadn't had time to do much else - he'd needed to get Alec back to the institute quickly. He'd never seen Alec like that before - disoriented and confused - and it had scared Jace more than he cared to admit. He was only grateful that Alec seemed to be alright, if a bit worn down.

Jace held his witch-light close to the bloodstain. It shimmered in the light, the green almost glowing with a life of it's own. He could only assume it was demon blood; no human, Shadowhunter or Downworlder bled like that. Maybe a faerie could, but he was pretty sure fey blood didn't shimmer or glow after it had left it's owners body. Whatever it was, Jace wanted to find it and kill it for hurting his parabatai.

He drew his seraph dagger and pressed it against the concrete, scraping up the bloodstain. The green stain curled into dried shavings, peeling off the concrete, and then to his amazement it seemed to shiver and move, as though it were alive. He stepped back and watched as the blood liquified, settling back into the pavement as though it had never been touched.

Jace pulled the swab kit he'd been carrying out of his jacket pocket and popped the cap off one of the clear tubes. He scraped the blood with his dagger again and quickly scooped some of the shavings into the plastic tube, placing the cap on tightly. He held the tube up in front of his eyes and watched, fascinated, as the dried blood turned to liquid again, settling in the bottom of the tube and bubbling occasionally. He glanced down - the blood on the pavement remained still and unmoving. 

'What the hell...' he muttered to himself. 

He tucked the tube back into his pocket and stood, raising his witch-light to cast the light across the alleyway. Something glinted in the light beside the dumpster, and he approached it, finding the splintered remains of one of Alec's arrows. He picked up the fragments and tucked them into his pocket as well. He felt a surge of pride, knowing his parabatai had done everything he could to fight off the demon, even if he couldn't remember it.

Jace sighed, and tucked his witch-light back into his pocket. He had to get back to the Institute, and there was nothing else for him to find here. Whatever had done this to his parabatai was probably still out there, prowling the streets in the dark, and the thought made Jace's blood run cold. He could only hope that he would be able to identify what kind of demon it was and where to find it before anyone else fell victim to it.

* * *

 

Alec walked slowly into the training room. He felt awful - his head was still pounding, even after the twelve hour sleep he'd just had, and he couldn't stop thinking about what he'd seen last night. He'd spent about ten minutes standing in front of the mirror that morning, closing and opening his eyes to ensure his face wouldn't change again. It hadn't, but that didn't mean he wasn't feeling on edge, apprehensive that he'd see something else he wasn't supposed to be able to see.

He knew he should have told Magnus about the hallucinations, but he couldn't bring himself to do it - Magnus had enough on his plate as it was. Alec wasn't even sure how he would start that conversation, and things were going so well with Magnus that he didn't want something like this to come between them. There was no point in worrying his boyfriend if Alec could simply work it out for himself.

He could hear the thuds and grunts of the other Shadowhunters training - he passed them by, staying close to the wall, wincing every time there was a particularly loud noise. He crossed the room to where Isabelle was training with Clary, coaching her on her footwork. He waited on the sidelines for them to take a break, leaning against the wall, not really watching them train, his head throbbing.

Isabelle suddenly appeared in front of him, a big smile on her face, her staff resting across her shoulders. Clary followed her, swigging from a water bottle, her red hair plastered to her face with sweat. 

'Alec. Hey. How are you feeling?' Isabelle asked.

He tried to smile, but he was pretty sure it came out as more of a grimace. 'Better, thanks.' _Lie._ 'Have you seen Jace?' If there was one person he could try to talk to about what he'd seen, it was Jace, though just the thought of trying to explain his hallucinations to his parabatai made him anxious.

'I saw him heading down to the labs about an hour ago,' Clary said.

'Okay, thanks,' he muttered, turning away. 

'Wait, Alec...' Isabelle chased after him, taking his arm. 'Are you sure you're okay? I mean, you look...' She trailed off, looking him up and down, and Alec thought he must look awful for even Isabelle to mention it - she who had seen him at his sickest, his most hurt. The skeletal version of himself from the mirror flashed unwanted across his mind, and he mentally shook himself.  _It wasn't real._

Alec placed his hand over hers and squeezed it gently before tugging his arm free, repeating the words he'd already said too many times before:

'I'm fine.'

The Angel only knew if he actually meant them.

* * *

 

Jace had been waiting for nearly an hour for the scan to finish when Alec walked into the lab. Alec looked around the room and visibly relaxed when he saw there was no one else in there with Jace, his shoulders dropping and his head tilting forward, as though standing upright was like carrying something heavy. He sat in one of the desk chairs beside Jace with a heavy sigh, leaning forward on the desk and dropping his head onto his forearms.

'Head still hurting?' Jace asked.

Alec let out a grunt. 'It's like the worst hangover I've ever had,' Alec said, his voice muffled.

'Yeah, concussions can be like that. I thought you were using an  _iratze_?'

Alec lifted his head and gave Jace an irritable glare. 'It's not working very well.' Jace watched as Alec lifted his head and rubbed his temples, his eyes closed. 'I've even tried mundane medicine, but that hasn't done anything either.'

Jace nodded. 'Give it time. It'll be gone in a couple of days.'

'I hope so.' Alec grimaced at him. 'What are you doing down here?' he asked blearily, changing the subject. His eyes flicked up to the computer screen. The scan was nearly complete.

'I went back to the alleyway where I found you,' Jace explained.

'Did you find anything?' Alec asked. He was staring at the computer screen intently, as though watching the scan would make it go faster.

'Green blood, so we can be pretty sure it was a demon that attacked you since I don't know what else it could be. And one of your arrows, but I suspect you won't want that back.'

Alec raised his eyebrows in surprise. 'Green? What kind of demon has green blood?'

Jace tapped the computer screen. 'I'm waiting for the scan to finish so I can find out.' Jace looked closer at his parabatai. Alec looked thinner, somehow, his face pale and strained. Jace could feel turmoil across their bond - Alec's head was bothering him more than he was letting on, and there was an underlying sense of confusion and fear. He couldn't imagine how Alec was functioning if the pain was bad enough to breach their parabatai bond like this.

'How are you doing, really?' Jace asked. He knew Alec knew he couldn't hide anything from Jace, even if he tried. 

'I...' Alec hesitated. 'I have to tell you something.' He sounded tired, scared, and Jace immediately sat up to attention. He didn't say anything, waiting for Alec to continue with bated breath, uncertain where this would be going. His parabatai hesitated, running a hand nervously through his hair. 

'This morning, I...saw something-'

The computer made a loud beeping noise and both Jace and Alec jumped at the suddenness. Jace glanced at the screen and saw the scan was done, sitting in a small pop-up screen. He was about to turn back to Alec when he registered what the pop-up said.

_Error. Source unknown. No records available._

He opened his mouth to tell Alec when he heard a soft gasp beside him.

'Alec?' Jace turned to see Alec heading for the door. Jace quickly closed the results tab on the computer and ran after Alec, but he was too slow. He saw Alec hurry across the hall and practically leap into the elevator, his face twisted in pain and confusion. His arm was held tightly across his chest, and Jace thought he might be hurt, but he couldn't feel any pain or injury. 

'Alec! Where are you going?' he said. Alec didn't seem to hear him, the elevator doors closing before Jace could get to them.

'Alec, wait!' He hit the button on the outside of the elevator, but the elevator was already rising. Jace stepped back, his mind racing. Alec was heading up, so Jace would follow. He ran for the door leading to the stairs. Something was going on - whatever had happened yesterday, it had changed Alec, even if Alec couldn't remember why. Alec's behaviour, combined with the useless blood scan...Jace's mind was running a million miles a minute as he raced up the stairs. 

What the hell was going?

* * *

 

Alec had tried. He'd tried to tell Jace what had happened last night, but Jace had been distracted, and Alec had started bleeding. 

He'd looked down, anxious, waiting for Jace to return his attention to him, unsure where to start explaining what he'd seen last night, to see his shirt sleeve coated in blood. He'd hurried from the room, hiding his arm from Jace. He knew it wasn't really there, it couldn't be, he didn't remember receiving the injury, but it looked real. It felt real.

He made it out into the hallway. There was a cut on his forearm, long and deep, and he wanted to cry when he saw it, the sight of the injury enough to shock his system into thinking he was hurt, his mind unable to understand what was happening to him. He didn't even remember what had happened to him yesterday, and now he was seeing things that weren't real.

He stumbled across the hallway to the elevator, smashing the button with his injured hand, pressing his good one against the cut, trying to stop the blood flow. He could hear Jace calling after him, but he ignored his parabatai, afraid Jace would see the blood, but also afraid Jace wouldn't. His brain was a haze of thoughts, flying across his mind like trees caught in a tornado, with one logical thought coming into focus - he was hurt, so he had to get to the infirmary.

_But the injury isn't real._

He jumped into the elevator as it opened and slammed the button for the infirmary, watching Jace run towards him as the doors closed. He couldn't find the words to explain to Jace what was happening, so he said nothing at all, and that might have been worse.

In the quiet of the elevator, unbidden memories came to the forefront of his mind, disconnected pieces of time he didn't recognise and couldn't put into order.  

_He'd been following someone - a man in red. There was an alleyway. He was choking..._

Alec slid to the floor of the elevator, breathing hard, his knees drawn up to his chest. He was still bleeding - no matter how many times he closed his eyes and wished the cut to disappear, it didn't - so he focused on the memories, grasping at them like they were a lifeline, but it was like they were made of water and his hands were made of nothing, the memories slipping through his fingers and melting away.

The elevator _pinged_ and the doors slid open. Alec looked up to see Isabelle and Clary in the doorway, and he was thankful it was them and not another Shadowhunter. Isabelle rushed to his side immediately, grabbing him, her voice thick with fear. Clary stood close behind her, watching the scene with wide eyes.

'Alec? What happened, what's wrong?'

He felt like a child, upset and afraid and _small_ , breathing way, way too fast. 'Do you see it?' he whispered, his eyes fixed on Isabelle, removing his hand from his injured forearm and showing it to her. She looked at him strangely, glancing around the elevator as though looking for a ghost.

'See what?' she asked slowly.

Alec looked down at his arm and let out a groan of frustration. The cut was gone, and his sleeve was clean.

_It wasn't real._

It was official. He was losing his mind.

**Notes for the Chapter:**

> Hello again! I intended to post this morning, but I had a busy day so here it is now. I've taken some liberties with the Institute and aspects of the narrative (do they even have a "lab"?) but I hope you can understand considering that this fan-fiction. Thank you so much for reading, and please leave any feedback you have in the comments - I always love to hear what people think of my writing, good or bad! I'll try to post again as soon as I can! - jaw xx


	4. Curious Incident

**Summary for the Chapter:**

> A demon feasts.

The man in red crossed the street boldly, strolling in front of several vehicles whose drivers were forced to slam their feet on their brakes. Horns echoed loudly into the street, angry shouts and gestures directed towards the man in red. He smiled, sharp teeth flashing in the headlights of the cars, but he didn't turn, his eyes fixed on the the building before him. He leapt onto the curb and pushed past a group of pedestrians, pausing before the door of the building on the corner. The hospital's red neon sign glowed brightly against the dark grey of the sky. 

The man in red headed inside, pushing back the hood that covered his marked head. He could feel his human form disintegrating around him as he moved, the edges fraying at the seams like a pair of worn socks. It was high-time he found a good meal, else his body would fall apart completely and his true form would be revealed to all who looked upon him. He supposed that Shadowhunter would have made a decent meal if he hadn't found the nephilim creature to be so...disgusting. The Shadowhunter wouldn't have been his food of choice, but perhaps he would have thought differently had he known it would be so long until his next meal.

He approached the hospital reception. The receptionist was a young woman, her hair tied back into a neat bun. He licked his lips at the sight of her pretty pink skin, the curve of her jaw, the plumpness of her cheeks. He almost didn't hear her when she spoke, his mouth salivating at the sight of her. 

'Can I help you?'

He smiled at her, and she stared back, her eyes welcoming but wary. Humans were stupid beasts, he'd found. They were animals waiting for the slaughter, so unused to being prey that they'd forgotten they weren't the scariest things out there in the dark.

'The neonate ward. Where is it?'

The receptionist frowned. 'I'm sorry, visiting times are over. You can come back tomorrow at nine.'

He narrowed his eyes. He wasn't used to people telling him no. 'I have an urgent appointment in the neonate ward.'

'I'm afraid I have to insist, sir. Visiting hours start again in the morning.' 

He almost laughed. She was defiant, and yet so fragile. If she insisted on denying him, she would have to suffice. It was such a shame. But, there was always a next time.

He rapped the counter with his knuckles and she relaxed, perhaps expecting him to leave. Instead, he turned his vessel to smoke with barely a thought, reappearing behind her in an instant. She flailed at his sudden appearance, almost falling out of her chair. Her eyes bulged with the impossibility of what he had just done, and before she could make any more noises he clamped a taloned hand over her mouth.

'As I told you before,' he said.'It was a very urgent appointment.'

He licked his lips, his tongue running over his fangs, tasting the air.

He was starving.

* * *

 

Alec rubbed his eyes with his fingers. He was so tired that he felt like sand was caught behind his eyelids, scratching painfully at his eyeballs. He was scared to try and sleep, worried he would see more strange things when he woke up. Or maybe he wasn't sure he would wake up at all. 

'How's your head?' 

Alec's eyes snapped open and he saw Isabelle standing beside the infirmary bed, holding a glass of water out to him. He accepted the drink gratefully, taking a few gulps before placing it aside. His stomach gurgled uncomfortably, and he realised he couldn't remember the last time he'd eaten.

'Better, actually. Hungry,' he admitted. Now that he thought about it, his headache was the least of his worries, having subsided somewhat since last night. That was something to be grateful for. 

'I called Magnus for you,' Isabelle said, sitting on the bed next to him. She hadn't gone far since his episode in the elevator. It was like she thought he was made of glass, as though if she looked away for a moment, he would shatter.

Alec nearly spat a mouthful of water across the bed, swallowing with some difficulty. 'Izzy, I didn't want him to worry about me-'

'Alec. He'd want to know. And besides, he could help us.'

Alec sighed, and then nodded. 'You're right.'

Isabelle grinned. 'When am I ever wrong?'

The sound of voices sounded outside the infirmary, and then the door opened. Jace and Clary came in, Jace holding a laptop, pointing at the screen. 

'-see, I told you. No results. This demon isn't in the database!' Jace was saying.

Clary rolled her eyes and took the laptop off Jace. The two of them stood at the foot of Alec's bed, crowding around the laptop. After a few moments, Clary looked up and frowned. 'Okay. You're right. There aren't any results.'

'So we've got no idea what kind of demon we're dealing with?' Isabelle asked, listening intently to the exchange. 

'Well, we know it's definitely a demon. And we know what it did to Alec,' Jace replied. 'Memory loss, hallucinations. That's got to count for something.'

'Hang on. We don't know if the memory loss was caused by the demon or Alec's concussion,' Clary pointed out.

'And there are about a dozen demons I could name that cause hallucinations,' Isabelle added. 

Jace sighed. 'Then we're back to square one.'

'Maybe if we-'

'Hey!'

Everyone turned to look at Alec, and he regretted drawing attention to himself like that. He wished he could sink through the mattress of the stupid infirmary bed and hide under it, but then he didn't think hiding under the bed would actually make anyone think he was less insane. 

'Can we stop talking about me like I'm not here?' Alec snapped at the others. 

'Sorry,' Clary said meekly. She passed the laptop back to Jace and then sat on the infirmary bed beside Isabelle. 

'Alec,' Isabelle said. 'Is there anything else you're not telling us? Something you remember, or something else that's happened?'

Alec thought back to the flashes of memory he'd been seeing. He hadn't mentioned them yet, and maybe it was because he couldn't make sense of them. 'No,' he said, too quickly. Isabelle raised her eyebrows at him and he coughed sheepishly. 'Okay. Maybe I have been remembering some stuff.'

Jace sat on the infirmary bed on the other side of Alec. 'Like what?'

Alec waved his hands uselessly, unsure how to describe what he'd felt. 'Like...the colour red.'

Jace raised his eyebrows. 'The colour red?'

'I didn't say it was anything helpful.' Alec shifted on the bed, looking down at his legs. 'This isn't easy, you know.'

Jace sighed again. He looked as exhausted as Alec felt. 'I'm sorry, I know. Let's just...start at the beginning, work through it again.'

'Are there any records of demons that aren't on the database?' Clary asked.

'Not that I know of,' Isabelle said. 'There might be a couple of old books in the library, but I doubt it. Hodge was meticulous when it came to gathering information like that, so I doubt he missed much.'

'I'm going to check the library,' Clary said. She climbed off the bed and swept out of the room with that determined walk she had. She was similar to Jace in so many ways, Alec noted, even if they weren't related. Stubborn, always on the move, focused on trying to save someone. It just so happened that this time, that someone was Alec. He wasn't sure he liked that concept very much.

'What else do you remember?' Isabelle asked him, cutting into his thoughts.

He blinked and opened his mouth to try and explain, but it was like the words were stolen from his lips. He tried again, but nothing came out. 

'Alec?'

He tried to take a deep breath to steady himself but it was like the air wouldn't enter his lungs, and when tried again it was harder to inhale. His brain finally caught up with his lungs and he choked on the truth. 

He couldn't breathe.

Panic set in, the kind of panic you felt when you get caught underwater and you don't know which way is up - dizzying, frightening panic.

'Alec!'

Jace's face was all Alec could see, but there was nothing Jace could do to help him. This wasn't real, wasn't affecting his parabatai. This was all in his head, the one place Jace couldn't help him.  

He made eye contact with Isabelle and he tapped his chest quickly and repeatedly, his hand shaking.

More memories flooded his brain, unwarranted and unwanted, showing their ugly faces now, of all times. Alec couldn't stop them from coming, so he succumbed to it, unable to fight them anyway.

_The colour red. Green eyes that flashed in the dark. There was a hand around his throat, squeezing tightly, taloned fingers digging into his skin, and a voice that hissed: 'I was going to kill you quickly, Shadowhunter...'_

His chest was tightening, like something was holding it and squeezing the life out of him.

'Jace, what do we do?' Isabelle's voice was reaching a pitch he'd never heard before.

'Alec, listen. It's not real. You can breathe, okay, you can breathe...'

His oxygen-starved brain was burning. His chest was aching.  _Let me, let me breathe, please, let me breathe-_

The doors to the infirmary flew open.

* * *

 

Magnus was pissed. 

Isabelle had called him not twenty minutes ago.

'Magnus.'

'Isabelle. To what do I owe the pleasure?'

'We need your help. Something's wrong with Alec.'

Magnus was already moving, pulling his coat off it's hook by the door. 'What happened?'

'We think he was attacked by a strange demon last night. He's just told us he's been seeing things. Hallucinating.'

Magnus paused, one arm in his coat, and clenched his fist around his phone. 'Hallucinating,' he said flatly.

'Yes.'

'I'll be there as soon as I can.'

He wasn't mad at Isabelle. He was mad that Alec hadn't told him. 

He'd known something was wrong last night, when he'd found Alexander in the bathroom, shaking and looking like he'd seen a ghost. Something about him had seemed...off, his behaviour so unlike the Alexander Magnus had come to know. He'd played it up to Alec's injury, but Magnus should have known better than that. He should have recognised the signs, pushed Alec to tell him the truth. He'd thought Alexander would come to him if there truly was something to be concerned about.

Apparently, he'd been wrong to assume that.

That made him infuriated more than anything - the man he loved couldn't tell him when he was hurting, even after everything they'd been through together. 

He approached the Institute's infirmary now, brushing past other Shadowhunters, ignoring their greetings and stares, focused only on one thing - getting the truth. Getting answers.

He used his magic to kick down the infirmary doors. There was nothing like making an entrance to show others how frustrated you were - plus, property destruction was sometimes therapeutically necessary for the soul. At least, that's what Magnus told himself.

Alec lay on one of the infirmary beds, Isabelle and Jace on either side of him, and Magnus felt a jolt of fear run through him when he saw Alexander, lying prone. Alec's mouth was gaping open like a fish's, his hands clutching at his neck and chest. Jace and Isabelle turned to stare at him.

'He can't breathe,' Jace said.

Isabelle's words echoed in Magnus's ears. _'_ _He's been hallucinating.'_

Magnus ran for the bed, throwing aside his annoyance, his magic curling in his fingers, blue and white and sparking. He pressed his hand to Alec's chest and allowed his magic to flow into Alec, spreading up Alec's torso and shoulders and bleeding into his mind. Magnus closed his eyes, concentrating. There was something dark, something hiding deep within Alec's consciousness, playing on his fears, inflicting pain and suffering. Magnus tugged at the tendrils attached to Alec, the one's controlling him, forcing him to think he was suffocating. The darkness jerked back at Magnus's touch, afraid.

 _'Alexander,'_ Magnus said. His was voice imbued with magic, deep and thunderous and echoing both in the room and within Alec's mind. Alec's eyes searched wildly until they found Magnus's, wide and fearful and fading. The darkness inside Alec resisted, but Magnus pushed back, and his magic won over, the darkness fading - not gone, but hiding.

 _'Breathe!'_  Magnus commanded, pushing magic into the command.

There was a pause, and then with a huge, rattling gasp as Alec jerked upwards, gulping in lungfuls of air. Magnus retracted his magic, but he left his hand on Alec's chest, feeling the hard thudding of Alec's heart under his fingers - his reassurance that Alexander was, indeed, still alive. Alec continued to take deep breaths, leaning into Magnus's touch. He reached over and grabbed at Magnus, pulling Magnus towards him like he was Alec's lifeline.

Magnus held him back. Confrontation could wait; his boyfriend needed him.  

'Alexander,' Magnus said calmly into Alec's hair, his arms curled protectively around Alec's body. 'Would you care to explain to me what is going on?'

**Notes for the Chapter:**

> I wrote most of this while chugging Bailey's Irish Cream liqueur and listening to the Black Panther soundtrack...take that as you will.
> 
> Thanks for reading! I stayed up pretty late to edit this so I hope y'all enjoy it. Please leave any you have feedback in the comments, and I'll try to update as soon as I can!  
> \- jaw xoxo


	5. Mind Over Matter

**Summary for the Chapter:**

> A plan to uncover the demon's identity is concocted, and Alec's condition gets worse.

Magnus picked up the blanket from where it was sitting on the chair in his bedroom. He headed back to the main room of his apartment, smiling slightly when he saw Alec asleep and draped across his sofa, long limbs hanging off the edge of the couch. Alec had passed out almost the second he'd laid down, despite his protests that he wanted to help.

They'd decided it would be safer for Alec here, not to mention more private. Alec was an integral part of the Clave, on the path to leadership, and there were already enough things to make others question his future, including Alec's involvement with Magnus himself. No, it would be better for everyone if Alec was kept far away from the other Shadowhunters right now. And this way, Magnus could protect him if something else happened.

Jace was seated next to Alec in one of Magnus's armchairs, an enormous book open in his lap. Magnus couldn't remember the last time he'd seen Jace reading - perhaps never. Isabelle and Clary had stayed to search the library at the Institute - so far, none of them had come up with any ideas as to what kind of demon they were dealing with. 

Magnus approached the sofa and draped the blanket over Alec's sleeping form. Alec shifted, curling further into the sofa, his hand reaching up and clutching the blanket. Even when he was asleep, he looked tired. Magnus wondered if this was a new development, or if Alec had looked like this for some time, and Magnus simply hadn't noticed it.

'Find anything?' Magnus asked Jace in a low voice. Jace shook his head in response, his eyes trained on the page he was reading. Magnus sighed and made his way over to his drinks table. If there was ever a time for a martini, it was now.

'We just don't have enough information,' Magnus continued, pouring himself a vodka. He paused, then poured a second one for Jace. He added ice and then rejoined Jace, placing the second glass in front of Jace, looking down at Alec as he drank. The vodka burned in his throat and chest when he swallowed.

'There was a demon attack,' Jace said, repeating again what Magnus had already heard half a dozen times. 'Hallucinations. Memory loss. And the presence you felt in Alec's head.'

Magnus finished his drink and sighed. The vodka wasn't making him feel much better. 'If only Alexander could remember what happened, we might have a chance at working out what's going on.'

There was silence for a few moments, and then Jace jerked his head up. 'Magnus.'

Magnus locked eyes with Jace, and immediately shook his head at the look Jace was wearing. 'He won't agree to that,' Magnus said fervently. 'Why do you think I haven't asked him?'

Jace closed the heavy book and picked up the vodka in front of him. 'We don't have any other ideas.' He threw his head back, downing his drink in one gulp.

'Even _if_ he agrees,' Magnus continued. 'I don't even know if it's possible.'

Jace tossed the book onto Magnus's coffee table with a heavy thud. The sound woke Alec, who looked around wildly until he recognised his surroundings. 'What is it?' Alec mumbled, rubbing his eyes and relaxing back into the couch. 'Did you find something?'

Jace glanced over at Magnus, who shook his head slightly. Jace ignored him. 'We have an idea,' he said.

'Your parabatai has an idea,' Magnus emphasised. He could have cheerfully strangled the blonde Shadowhunter for trying to include him in this awful idea.

Alec propped himself up on his elbow and glanced between the two of them. 'Do I get to know what it is?' he asked, when neither of them elaborated.

Magnus sighed. 'Jace thinks I can retrieve your memories.'

Alec hesitated. 'By using your magic? Would that work?'

Magnus paced back and forth, rolling his drink between his palms. 'Theoretically? Yes. But it'll be dangerous, and I don't know what it could do to you if I mess around with you memories...' Magnus sighed, pressing his thumb into his forehead. 'It's such an invasion of privacy, Alexander, I-'

'You have to do it,' Alec interrupted.

Magnus raised his eyebrows in surprise. 'Are you sure?'

'The demon that attacked me is still controlling me,' Alec said. 'I can't keep this up, and I'd rather you did this than go to the Silent Brothers...'

Magnus took a deep breath. 'Okay. With your permission.'

Alec caught Magnus's eye, and Magnus was saddened to see the exhaustion in them, the fear. 'I'm sure. I trust you, Magnus.'

* * *

 

Alec was seated on a cushion on the floor of Magnus's study. The lights had been turned off and replaced by candles. Magnus was sitting across from him, so close that their knees were almost touching. His eyes were closed, his lips moving soundlessly. In any other circumstance, Alec would have thought this was an oddly romantic evening - except for the fact that he felt awful and his nerves were shot, his instincts telling him to move, to fight, to run. All he could think about was the next time his mind would play tricks on him, his body plagued with apprehension at seeing something that wasn't real. 

Alec could hear the voices of his friends through the door to Magnus's study, and wished with everything he had that he could be out there with them, that this could be happening to anyone but him. However selfish that thought was, in that moment, he didn't care. 

Magnus's eyes flicked opened, and Alec noticed they were his cat-eyes, the ones Alec rarely saw but found intriguing. Magnus's eyes flashed luminously in the low light, and Alec was vividly reminded of another pair of glowing eyes he'd seen recently, familiar but frightening, but the memory of them was hidden from him. 

'Ready?' Magnus asked. Alec nodded.

'Close your eyes.' Alec did so, sending a quick prayer to whatever deity was listening that this would work, that they would learn the truth of what had happened to him and how to fix it, once and for all. The last thing he saw were Magnus's hands moving, his magic spreading out towards Alec in a cloud of blue energy.

Magnus's magic was cool and calm as it entered his mind, soothing his unease. With it came Magnus's presence, wild and intelligent and vast and kind.

_'I told you to relax.'_ Magnus's voice echoed in Alec's mind, rich with power.

Alec shifted in his spot on the floor. 'Sorry.'

_'This will only work if you stay calm. I'll try to be as gentle as I can, but I don't know what the demon did to you. I can't make any promises that it won't hurt or trigger something,'_ Magnus explained. Alec knew Magnus didn't want to hurt him - he could feel the unwillingness to proceed - but he didn't see that they had any other choice.  

Alec braced himself against the floor. 'Do what you have to do,' he said. 

Tendrils of Magnus's magic began to push into Alec's mind, searching through memories and moments from his life. It was a strange feeling, and it made Alec's muscles tighten and his skin prickle. The thought of someone digging around inside his head, reading his every thought, able to access his memories and emotions...it made him uncomfortable, to say the least. He'd been possessed before, and these hallucinations, the presence Magnus had found in his head - he was certain he was being possessed again.

But it was Magnus. Magnus, who he loved. Magnus, who he trusted.

Magnus, who he'd lied to. 

Alec felt the sharp sting of remorse and Magnus paused on his search.  _'Alec.'_

Alec gritted his teeth, trying to push away the intrusive thoughts. 'Sorry. Keep going.'

Magnus pushed on. They stayed like that for some time, until Alec felt Magnus come across the day he'd been attacked - _had it really only been two days ago?_ \- and Magnus grasped the memories with his magic. There was a gap, like someone had broken into Alec's mind and erased the memories, like you'd erase a security tape.

_'Ready?'_ Magnus asked. He was still hesitant, holding back, and Alec swallowed dryly. 

'Do it.'

Magnus's magic surged around the memories, and it was like they were playing out in front of Alec's eyes. The strange sensation of deja vu enveloped him, the hairs on the back of his neck standing to attention. The scenes were foreign to Alec, like he was watching them happen through the eyes of a stranger: following the man in red. The fight in the alley. The ability of the demon to teleport. Alec getting thrown across the alleyway and hitting his head.

Something brushed the back of Alec's subconsciousness, and his neck tingled like someone was walking up behind him. He pushed the sensation aside, watching the memories, wanting to know the truth.

He felt Magnus's revulsion when the demon picked him up by the throat and it's mouth opened like a python's. Something was crawling out of the demon, crawling  _inside Alec;_ a fragment of the demon. Alec felt horror surge through him like a tidal wave. There was a monster inside of him. The thought alone was nearly enough to break him.

Alec felt Magnus extricate himself from his mind when it was over, the coolness of Magnus's magic leaving him like he'd stepped out of a cold shower into a summer's day. Alec opened his eyes to see Magnus staring at him. 'Alec...I promise, I'll do everything I can to get you through this,' Magnus said.

Alec nodded, reaching out for Magnus's hand, needing the support, something to hold onto. He'd lost control of himself once before. He wasn't sure he could get through that again on his own. 

His fingers grazed Magnus's, and the moment they touched something exploded inside Alec's head. Heat flooded his mind, and he let out a moan. He was falling, falling into heat and fire and black, falling away from the world that Magnus occupied and travelling somewhere else entirely. He heard Magnus's voice call his name. Alec tried to respond but all that came out of his mouth was a cry of pain. The heat was growing more intense. He couldn't open his eyes. He couldn't move his body.

_This is just another hallucination,_ he told himself. _It's not real._

But then he felt the remnant of the demon crawling around inside his mind, it's presence stronger than it had been before, and Alec realised that he was no longer hallucinating. The fire inside of him was real. Alec shied away from the creature and the darkness it exhumed, the fire it was pouring into his body, but there was no escape. The creature was visceral, a solid presence in his head that called for his blood, his life. The memories that had been lost to him until moments ago echoed in his head, words spilling out into his mind:

_'I know exactly how to make your death...interesting.'_

The darkness was all around him, consuming him. For the second time in his life, Alec lost control of his own self.

He was burning.

* * *

 

Magnus withdrew from Alec's mind as quickly as he could, horrified by the images he'd seen through Alec's eyes. Magnus saw a tortured man sitting before him, a man who had been broken by what had happened. He reached out to take Alec's hand when Alec jerked and fell, collapsing on the floor in a heap, crying out in fear. 

'Alec?'

Magnus dove across the small space between them, placing his hands on Alec's chest, just as he had in the infirmary only hours before. Alec was hot, his skin burning like he was feverish, and Magnus wondered if this was because of the possession or if he'd caused this. Jace burst through the door into Magnus's study, his eyes bright, his hair plastered to his forehead with sweat. Clary was close behind him, clutching at his arm, but he shook her off.

Magnus frowned; whatever was happening to Alec was real enough to spread across the parabatai bond, affecting Jace as well.

'What's happening?' Isabelle asked from behind Jace, looking from Magnus to Alec.

'I don't know,' Magnus said.

'Find out,' Jace said through clenched teeth, his cheeks flushed red. He dropped to his knees by Alec's head, grabbing his parabatai by his shoulders and holding him tightly. Alec let out a groan at the touch. 

Magnus hesitated. 'I could kill him if I go back in,' he warned Jace. 

'You have to do something!' Jace cried.

Magnus paused, and then pushed his magic into Alec, trying to work his way back into Alec's mind. It was almost impossible - Alec's mind was an inferno, the fire and darkness burning so strongly that Magnus was afraid for not only Alec, but himself. He focused with some difficulty on the creature dwelling in Alec's mind. He felt hatred radiating from it, directed at both Alec and Magnus's presence. It was a simple-minded beast, a monster following it's master's orders: kill the host. The fever was simply the beginning of the process, Magnus realised.

Magnus dug deeper, clawing at the creature's mind and absorbing what information he could. It's master had surfaced at a time when the walls between worlds were weakest, clawing it's way out of Edom to find a world where it could feed. Magnus felt the creature fighting back, and Alec shouted, the strain becoming too much. Magnus clung on for a few moments more, and then he found something useful - a name. 

He pulled out of Alec's mind with shaking hands. Alec was gasping for air, but relaxed somewhat once Magnus was gone. Jace looked up at Magnus expectantly. 'Well?'

Magnus sat back weakly. It was worse than he'd thought. He blinked a few times in the dim light. 'I can't do anything more without killing him,' he said. He looked up and recognised the hopelessness on Jace's; he felt it himself.

'Did you find out what happened?' Clary asked. She was crouching beside him.

'Yes,' Magnus replied. 'He's being possessed by a fragment of a demon, and it took over while I was inside his head. I couldn't do anything when I went back in, but...'

'What is it?'

'I managed to get the original demon's name.'

Jace's head whipped up. He was breathing heavily, the sheen of sweat on his face reflecting the candlelight. 'What is it?' he asked.

Magnus licked his lips nervously. 'An Asag.'

**Notes for the Chapter:**

> Hello, hello! I meant to update last night but things got busy, and I wasn't overly happy with the chapter then anyway. I hope you guys liked it, and thank y'all for reading! I'll try to update again in a couple of days.
> 
> \- jaw xx


	6. Summoning

**Summary for the Chapter:**

> Magnus attempts to summon the demon responsible.

_Alec stepped lightly across the training room floor, the practice baton swinging in his hand. He and Jace had the place to themselves. Alec watched Jace mirror his movements across the room, his feet crossing over one another in well-practiced movements._

_Alec paused and then lunged, the practice sword swinging overhead, slicing down at Jace's face. Jace moved to block the blow and they parried back and forth for a few seconds before Jace managed to loop his baton over Alec's, flipping the sword out of Alec's hand with ease. The baton_ thwacked  _when it hit the floor. Jace lifted the point of his sword up to Alec's neck, touching his chin lightly, and grinned. Alec lifted his hands in mock surrender._

_'I win,' Jace said. He lowered the baton from Alec's throat and bent to pick up Alec's practice sword, reversing it and handing it back to Alec. 'You owe me a drink.'_

_'Best two out of three,' Alec said, snatching the baton from Jace. He took a couple of steps back and took his stance, bending his knees slightly and bouncing on the balls of his feet._

_Jace laughed, but copied Alec's stance. They circled each other again, turning slowly around the room. 'You're going to lose, Lightwood,' Jace said._

_Alec smirked. 'Maybe.'_

_A few moments later and Alec was on his back on the ground, glaring frustratedly down the length of Jace's practice baton._

_'You were saying?' Jace said, cocking his head to one side._

_Alec slapped the baton aside and sat up. 'Best three out of five.'_

_Jace laughed again. 'I think we both know what'll happen if we keep going.' He offered his hand to Alec and Alec took it, allowing Jace to help haul him off the ground. Jace bent to pick up Alec's practice baton again, this time placing them back on the rack at the side of the room. Jace picked up his jacket and headed out of the training room, down the long hallway that led back to the living quarters._

_'Where are you going?' Alec called after him._

_'You owe me two drinks,' Jace replied over his shoulder._

_Alec grinned and hurried to follow his parabatai. As he walked down the hallway the ground suddenly swayed underneath his feet. He paused, his arms held out for balance. 'Jace...' he said uncertainly._

_Jace turned and laughed at him, apparently noticing nothing. '_ _Come on, Alec!' he called out._

_Alec took a step forward and the floorboards rippled and shook; a second step, and the floorboards cracked, the wood splintering out from Alec's boot. Alec looked back up at Jace and he recoiled when he saw Jace staring at him, slack-jawed, his smile replaced with a look more akin to hunger. Jace's eyes were completely black, and he stumbled towards Alec, his feet dragging._

'You failed, Alec,'  _Jace said, his voice booming and grinding unnaturally in Alec's ears._ 'You're dying.'

_A_ l _ec shook his head in confusion. Nothing about this was making sense. 'Jace!' he cried. He tried to step towards Jace, but the floor was breaking away, the wooden floorboards crumbling to pieces around him._

'You're dying, Alec,'  _Jace repeated._  'And we're all going to die, too.'

_Black smoke poured out of Jace's mouth and nose, curling around his body. The entire building was breaking apart, the floors, the ceiling, the walls. The floor underneath Jace cracked, and Alec cried out as he watched his parabatai fall, Jace's limbs flailing and flopping like a doll's until he was swallowed by the pool of fire below._ _Alec screamed when his parabatai disappeared into the flames. The fire was rushing towards him, the flames biting at his body._

_And then Alec was consumed by darkness._

* * *

 

Magnus and Jace were desperately trying to hold Alec still, but Alec kept fighting them off, delirious, thrashing his limbs wildly at their touch. He was crying out for Jace, for Magnus, for Isabelle, but he didn't respond when Magnus tried to calm him.

'We're here, Alec!' he cried. 'We're right here.' But Alec was unreachable, trapped inside his own head. It took everything Magnus had to keep it together as he watched Alec suffer.  

'Izzy, hurry up!' Jace shouted. Isabelle was struggling to lift Alec's shirt up enough to get to his  _iratze_ rune. She managed to tug the shirt up Alec's side and then ran her stele over the rune. The rune stayed black, the usual activation shimmer absent. Isabelle tried again, but the rune didn't react.

'It's not working!' she cried. She stepped back helplessly, looking around at the others. 'What do we do?'

'Hold him still,' Magnus ordered. He let go of Alec's arm and pressed his hand into Alec's chest. He couldn't still the inferno in Alec's mind, but he could calm him enough to stop him from hurting himself or others around him. He spread his magic into Alec's body, telling him to sleep, and Alec resisted for a moment before relaxing into the bed. He continued to make small moans of pain, but he no longer fought them. Jace eased his grip on his brother's body, using Magnus's night stand to keep himself standing. 

'What did you do?' Isabelle asked. 

'Sedated him,' Magnus explained, blinking rapidly. He felt light-headed. 'I don't know how long it will last.'

'Magnus,' Jace said quietly. 'Now would be a really good time for you to explain what's going on.'

Magnus looked down at the floor, unsure of where to begin.

'Magnus!' Jace growled.

Magnus sighed. 'I don't know what I can tell you. Asag demons aren't exactly common.' 

'Surely you know something-'

'I don't, Jace!' Magnus snapped. 'I know nothing about these creatures except for stories I heard, years ago!' He took a deep breath. He knew he couldn't afford to be upset right now, but he couldn't help it. He was lost, knowing so little about what they were facing. And Alec's condition was deteriorating so quickly that Magnus was starting to panic at the thought of losing him. 

'Magnus,' Isabelle said firmly. 'Is Alec going to be okay?'

Magnus forced himself to respond calmly. 'I don't know. It's unlikely he'll last very long against the creature possessing him.'

'So what do we do?' Isabelle asked. She approached Magnus, grabbing his arm and squeezing it tightly. 'Magnus. What. Do we. Do?'

Magnus looked over at Alec, and all he wanted to do was hold him, tell him it was going to be okay, take him far away from all this. But it would be pointless, because Alec was dying. 'We have to find the demon, and kill it,' he said. 

'Will that work?' Clary asked. 

Magnus pressed his fingers into his eyes, rubbing until he saw stars behind his eyelids. 'I don't know. I don't know if my magic will work, or if your seraph blades will work, but I know that we can't just leave Alec like this and that demon is our only option.'

Jace was nodding. 'I agree. How do we find it?'

'Tracking?' Clary suggested. 

'I don't have anything that belongs to the demon,' Magnus said. 

'I do.' Jace ran a hand through his hair. 'I have some of its blood from the night it attacked Alec.'

'Where?' Magnus asked. 

'The Institute.'

Magnus cast a glance at Alec. 'We don't have time for you to get it.'He could feel dread curdling in stomach as he understood what he would have to do. He squared his shoulders and stood, composing himself. He felt nauseous, the first sign he was overextending his magic. He swallowed, pushing the feeling aside. He didn't have a choice but to use more. Magnus was aware of all eyes on him, and he forced himself to smile slightly, shoving the worry he was feeling behind a mask of determination.

'I have an idea,' he said, before turning on his heel and heading for the main room of his apartment. He heard Isabelle's heeled boots follow him. 

'What are you going to do?'

'I'm going to bring the demon to us,' Magnus said. He started pulling open the drawers on one of the cabinets in his apartment, pulling out candles. 

He had a demon to summon. 

* * *

 

Magnus was kneeling on the floor of his study. He'd cleared the furniture away with his magic, using some of his precious reserves just to save time. He was nearly finished drawing the pentagram on the floor, the five-point sigil a little rougher than he would have liked, but it would suit it's purpose. 

'Are you sure this is a good idea?' Clary asked him from across the pentagram. She was placing candles at each of the points of the star as Magnus finished them, the candlelight casting eery shadows across the room. Isabelle was standing behind Clary, watching carefully.

Magnus nodded, continuing with the pentagram. 'I can do this.' He wasn't necessarily lying; perhaps twisting the truth a little. He knew he could get the demon here, but holding it inside the protective circle was another matter entirely. He pushed the thought out of his head. They would deal with that once they'd summoned the damned thing.

'If you need help, I could-'

'Clarissa. I'm fine.' He gave her a tight smile to reassure her, but he was barely able to convince himself that he had the strength for this. She closed her mouth with a snap, her jaw clenching stubbornly as it always did when she wanted to say something she shouldn't. Magnus ignored her - it didn't matter if he was lying to her, and to himself. He had to do this for Alec, or they would lose him. Magnus would lose him.

'Magnus, what exactly are Asag demons?' Isabelle asked him as he worked. 'I've never heard of them before.'

'You wouldn't have,' he said. 'They're ancient beings, made of old magic. There are Mesopotamian legends about them that say they feed on human flesh. Sometimes they'd cause people to go mad with hallucinations and nightmares. I doubt there's any viable record of their existence in any Institute - they disappeared long before Shadowhunters had any form of records, and no one's seen one of them for centuries.'

'Until now.'

'Yes. Until now.' He paused. 'This one seems particularly hell-bent on causing as much chaos as it can while it's here.'

'Maybe it's been away for so long that it can't control itself,' Clary said. 

'Maybe.'

Magnus finished the pentagram with a flourish and dusted his palms of the white chalk. Clary lit the final candle and then stood, standing beside Isabelle. Magnus stood as well, fixing the shirt he was wearing. 

'Are we sure about this?' Clary asked. 

Magnus took a deep breath. 'No,' he said. 'But we don't have another choice.'

He raised his arms and began the incantation, the words of power flowing from his hands and into the pentagram. Gusts of air began swirling around Magnus, blowing as though there was a breeze inside the room. The candles flared brightly as he spoke, the fire shooting a couple of feet into the air. It was working. He reached out into the nether and felt the shadowy forms of demons. He called the name of the Asag and his magic pulled him in the right direction until he was hovering, poised to pluck the Asag from the void. 

Magnus reached the midway point of the incantation, when the ritual asked for an offering before he could continue. He bent, picking up the long knife he'd taken from the kitchen. He pressed the blade against his palm and heard Clary's sharp intake of breath as he made an incision across his skin. Blood welled out of the wound and he held his hand out over the pentagram, the blood dropping onto the white chalk. He kept his hand out until he was satisfied with the offering, and then pulled a handkerchief out of his pocket and wrapped his hand with it. There would be time for him to heal himself with magic later, but right now he needed every last ounce for the summoning. The pain only urged him onwards, focusing his mind and reminding him of the ordeal Alec must be going through.

Magnus took a steadying breath and continued with the spell, reaching out with his hands and his magic. The Asag was there, in front of him, and Magnus called him forth, drawing the demon's burning, angry, red energy towards his apartment. The summoning ritual was rough, drawing a lot of magic from him in the search for the demon. The Asag heard the call but it resisted, pulling back against Magnus's magic as though it was tugging on a leash. Magnus called again, invoking stronger words of power, and the Asag was forced to heed his words and appear before him.  

There was a rush of air, and then the candles flashed before settling back to their original size. The Asag materialised inside the pentagram in a cloud of red smoke, it's eyes glowing bright green. The Asag's eyes flashed towards Magnus's, it's mouth open in a toothy sneer. 

'Who dares call me away from my meal?' the Asag growled. It stepped towards the edge of the pentagram, pushing against the protective circle it made, and Magnus tensed, flexing his magic to hold the demon back. It held, for the moment, but Magnus could feel himself weakening ever so slightly. He was sure the Asag felt it too, because the demon smiled slightly. It leaned back from the edge of the pentagram, it's lip curling. 

'Explain yourself!' the Asag demanded, whipping it's head around the room. 'Why did you bring me here?'

'We want you to undo whatever you did to Alec Lightwood,' Isabelle said. She circled the pentagram, and Magnus saw something shining in her hand - her bracelet, in the form of a staff.

'I'm afraid I do not know of whom you speak,' the Asag said. It sounded bored. 'If he was a friend of yours, you have my condolences.' It's eyes flicked back to stare at Magnus, who was now starting to shake with the effort of keeping the protective circle up. His magic was wearing dangerously thin.

'Little warlock...' the Asag muttered. 'You've outdone yourself. How long can you keep this up?'

'Answer my question!' Isabelle said sharply, drawing the Asag's eyes back to her.

The Asag snarled in response. 'You will demand nothing from me, Shadowhunter. Now, free me!'

The corner of Isabelle's mouth pricked up in a smile. 'No.'

The Asag let out a roar. A clawed hand swiped at the wall of the pentagram and Magnus nearly lost control. He let out a grunt and pushed every lest vestige of magic he had left into the protective circle. He could feel the nausea in his stomach clawing up his throat, and he had to fight to keep standing as the magic poured out of him like sand in an hourglass. He knew now that he'd been stupid, had rushed into this without considering the consequences, and now he'd only made things worse. 

'Shadowhunters, warlocks, demons...' the Asag was muttering, more to itself than the rest of them. It looked at each of them individually, hungrily. 'All of you, thorns in my side. But, no matter; you'll all be gone soon.'

A sharp smile appeared on the Asag's face. 'I will eat you all.'

The Asag's form began to shake, it's edges blurring and shimmering until they were no longer edges at all. The demon's body expanded, stretching out and pushing at all sides of the protective circle. Magnus strained against the force but it was too strong, and he severed the connection. The protective circled snapped with a blast of energy. It rushed past Magnus and pushed him back onto the ground, making him skid across the floor and whipping around his hair and clothes. The candles were blown out, plunging the room into darkness. 

Magnus lifted his head, squinting in the dark. The Asag's form was glowing red, no longer in the shape of a man but now in the shape of a monster. 

The Asag's limbs were elongating, it's body growing thicker and rounder. It's arms and legs were thick and strong and covered in spikes, ending in taloned claws. The Asag's head was covered in dozens of eyes, all of which were glowing green. Large fangs protruded from it's mouth, and a heavy tail thumped onto the ground. 

The Asag roared furiously, the sound making Magnus's ears ache, and it's mouth opened wide, displaying several rows of sharp teeth. Magnus was looking right down it's maw and squirmed away from it once he saw the darkness inside the demon, remembering what had happened to Alec. He could already see more of the creatures, like the one inside Alec, crawling out of the dark, climbing their way towards the light. Magnus shouted for Isabelle and Clary - they had seraph blades, they could kill the creatures - but they couldn't hear him over the cacophony of noise. The black creatures spilled out of the demon's mouth, dropping onto the floor and crawling towards Magnus and the others like worms surfacing from soil.

The Asag closed it's mouth and shook it's head.  _'Remember this night as your last, warlock,'_ the creature snarled. It lurched backwards, and then turned, lumbering across the ground surprisingly quickly towards the window behind it. The demon flung itself through the glass, taking a sizeable chunk of the wall out as well.

There was a final roar as the demon disappeared into a cloud of smoke over New York City.

* * *

 

_Alec opened his eyes._

_He was lying on his back, his bedroom ceiling above him. He jerked up off the bed, looking around wildly, expecting to see Jace, or perhaps Magnus._

_'Alec, you're okay!'_

_He turned to his left to see Isabelle sitting by his side, her hand resting on his arm. He relaxed at the sight of her._

_'What happened?' he asked. He felt like he hadn't slept at all, like he'd had a bad dream but couldn't remember what it was._

_Isabelle smiled gently. 'We_ _were attacked. You hit your head, but you're alright now.' The smile faded. 'It's a shame, really.'_

_Alec frowned, staring at her. 'What?'_

_'I was hoping you wouldn't make it.'_

_The words stung unexpectedly. Alec drew his arm away from her uncertainly. 'Izzy?'_

_Isabelle got to her feet and paced back and forth beside his bed. The silver snake bracelet she wore slithered down her arm, stretching out into it's whip form. Isabelle curled the whip through her other hand as she walked._

_'You know, I've always been disappointed in you,' Isabelle said. Alec was edging away from her slowly, shifting across the bed. Something was wrong._

_'You've always been such a burden on our family, Alec,' she continued. 'You just won't go away, no matter what we do.'_

_Alec could feel the hurt burning in his stomach at Isabelle's words. 'Why are you saying this?' he asked her._

_Isabelle laughed. 'Because it's about damn time I did something about it. By the Angel, Alec, look at yourself.' She stopped walking, standing by the bed, her whip unfurling and trailing on the floor. 'You're pathetic.'_

_Alec looked up at his sister and he gasped in horror. Isabelle's skin was pale and waxen, her eyes black caverns that seemed to sag down her cheeks. She flicked the whip towards him and it curled around Alec's neck. He pulled at it, choking, but it wouldn't give._

_'I'll be so much happier when you're dead,' she said, laughing. Her voice warped, reverberating inside Alec's head like he was listening to a hundred Isabelle's at once. She pulled tightly on the whip, and white spots appeared in front of Alec's eyes._

_And once more, he fell into the void._

**Notes for the Chapter:**

> Hi everyone! I'm sorry I didn't update this sooner, it just took a while to get the chapter right. It's still a bit of a mess, but anyway, here you go. What did you think? Did this one answer questions or raise more questions? Do I really know where the plot is going? What are your theories? Let me know!
> 
> Thanks so much for reading! Just a heads up - my computer is going to be out of commission for a little while, so I'll try to update again as soon as I can, but it might be a few more days after today. 
> 
> \- jaw xx


	7. Hospitals and Horror Films

**Summary for the Chapter:**

> The group struggle to get their bearings after the summoning went awry.

The north wing on the fifth floor of St Mary's Hospital was closed for maintenance, the rooms dark and empty. The north wing's only occupant was a security guard making his rounds. He circulated the floor tiredly, stifling a yawn behind his hand. The night shift was long, and all he wanted to do was go home to his wife.

The security guard walked slowly towards the end of the ward, the skyline visible through the window set into the wall at the end of the corridor. He paused when he reached the window, admiring the view - New York really was the city that never slept. The skyscrapers glittered before him, car headlights flashing off the windows. He made to turn away when something caught his eye, and he looked back out at the street, peering at the dark blue sky above the hospital. There was a dark shape in the sky, falling past the buildings. For a moment he thought it looked like a person, but then he blinked and the shape was gone. 

The security guard shook himself, staring out into the street for a few more moments before coming to the conclusion it had been a trick of the light. He turned away and yelped when he bumped into a large shape that hadn't been there a moment ago.

The security looked up slowly, his knees turning to jelly as he took in the monster that stood before him - long, spiked limbs ending in claws; a massive jaw; razor sharp teeth. The security guard whimpered, his flashlight dropping from his hand with a clatter. His body jolted as something rammed into his chest and he opened his mouth to scream at the pain that followed, but all that came out was a pathetic gurgle. He looked down to see one of the monster's arms protruding from his chest, claws inside his chest. Blood bubbled up from his stomach, spilling out of his mouth and down his chin in red sheets. 

The Asag opened its mouth and snapped at the security guard, biting down upon his torso with ease. The Asag devoured the security guard quickly, the mangled corpse it left behind barely appearing human. 

The Asag turned, flashing bloodstained teeth in the light of the flashlight that flickered from the floor. The tiled floor cracked under its weight as it lumbered down the hallway on all fours, its tail scraping the floor and walls. 

The Asag was angry. That meddling warlock and it's Shadowhunter friends had drawn it away from it's last meal before it could eat, only to attempt to kill it. It wouldn't take to being insulted like this. The Asag would show that warlock exactly what kind of monster it was - one that could not be controlled by simple human creatures. 

The Asag inhaled deeply. It could smell humans up ahead and all around, the stink of their flesh making its mouth water and stomach growl. It ran its tongue over its lips, tasting the air, its mouth salivating with the anticipation of killing and tasting human flesh once more.

It was time to feed.

* * *

 

Jace could feel Alec slipping away from him.

The thought of losing Alec was a fear Jace had only ever considered briefly. He had experienced it a few times before - the time Alec had fallen off the roof of a building, or when he'd been bitten by a poisonous Ravener demon, or when Alec's soul had become trapped while looking for Jace - but this was another level of fear. This time, Jace felt useless, unable to help the person who meant the most to him. He was at a loss of how to help his brother, his parabatai, his best friend.

And that scared him more than anything. 

He could feel the residual effects of the fire inside Alec burning at his body and mind. Jace shook with fever, his skin fluctuating between too hot and too cold, sweat plastered his clothes to his skin. He called for Alec to come back to him, but Alec either couldn't hear him or couldn't do as he asked. It was like playing tug-of-war with a mountain - the weight was never going to shift, no matter how hard Jace pulled, but he tried anyway, even though he knew that whatever Alec was facing inside his head, he would have to face it alone. 

There had been silence for the last few minutes from the study, but Jace jerked his head up when he heard shouting. A loud roaring sound followed, and Jace leapt to his feet, staggering as he ran for the doorway, casting a solemn look back at Alec. He ran for the study next door and threw the door open. Inside, the room was chaos incarnate, wind whipping wildly around him like he had walked in on a hurricane. He couldn't see much in the dark, but his eyes were immediately drawn to the shape of the enormous monster which stood over the scratched pentagram on the floor. 

The monster bellowed a final time before turning and flinging itself through the window with a shattering crash, creating an enormous hole in the wall. The wind died down somewhat, and the quiet that followed was almost eerie, broken only by the sound of the city through the hole. 

Jace could hear scuffling and panting in the dark, and he fumbled for the light switch on the wall beside him. The lights mounted on the walls lit up, flickering slightly, illuminating the wreck that had been Magnus's study. Plaster and glass and wood were strewn across the floor around the hole. Candles had been thrown across the room, leaving hardening trails of wax behind them. Across from Jace, Isabelle was helping Clary to her feet, their weapons in hand. To his left, Magnus was on the floor, crawling backwards on his elbows, his eyes fixed on the dozen or so creatures made of shadow that crawled across the floor towards him. 

Jace staggered forwards immediately, drawing his seraph blade, and sliced down at the dark creatures, cutting through them as though they were made of butter. He dispatched them quickly, their shadowy forms piling upon the ground. Jace grinned when he was done and turned to Magnus, reaching down to help the warlock to his feet. Magnus took his hand, but he didn't return his look of triumph. 

'I think you made it worse,' Magnus said, pointing to the floor. Jace turned to see the creatures were moving, black smoke surrounding their bodies and elongating their shapes. The pieces he'd severed from the creatures were growing into new creatures, and then the shadow creatures were back on their feet, only now there was more of them. 

Jace readied his weapon once more, placing himself between the creatures and Magnus, and he took them out again, one by one, only this time he did so with a sense of apprehension. Every time he cut one down, another took its place. Clary and Isabelle joined in, fighting their way to Jace's side, but even with their help the creatures continued to multiply too fast for them to account for it. Twenty creatures turned into thirty, which turned into forty. Jace could feel himself beginning to tire, his arms growing heavy. 

'Its no use!' Magnus shouted from behind Jace. 'Your swords aren't going to work!' The group backed away, drawing the slow-moving shadow creatures after them. They were surrounded, the creatures forming a semi-circle in front of the door. Jace was nearly pressed up against the back wall of the room, his sword flashing as he fought off the creatures one at a time. 

'What's the alternative?' Jace growled, cutting through the creatures as fast as they could come at him. 

Magnus hesitated, then shouldered past him, raising his hands. Blue energy sparked in his fingers, spitting and flickering before igniting properly, coming to life with a shudder, like a car engine after it stalls. 'Get down!' Magnus shouted, the blue energy forming into a bridge between his hands. The Shadowhunters ducked as Magnus thrust his hands forward. Blue light spilled forth, spreading across the room in a powerful wave, knocking the dark creatures back. 

Magnus held the blast for a few seconds and Jace watched as the creatures disintegrated before his eyes, smoke-like forms turning to dust and settling upon the floor. The blue energy dissipated once the creatures were gone. 

'Are they gone?' Clary said as she rose to her feet, her seraph blade still in her hand, poised to strike. They hesitated for a few moments, but the dust didn't reform. Magnus had sent them back wherever they had come from. 

'Amazing,' Isabelle muttered. She flourished her staff and it snapped back into its bracelet, snaking up around her forearm.

Jace, too, was impressed by the display of power. He was about to say so when Magnus stumbled forwards, dropping to his knees, retching. Jace approached Magnus's side uncertainly. Magnus's body shook with the effort of throwing up and then he straightened, wiping his mouth with a shaking hand before climbing to his feet. 

'Are you okay?' Clary asked. 

Magnus grimaced. 'Not so much,' he admitted. He swayed on the spot and made to leave the room, but he almost fell, stopped only by Jace's hand supporting his arm. Magnus let Jace help him out to the main room of his apartment, where he leaned against the back of the sofa, pale-faced and breathing hard.

'The summoning spell didn't do much but use up my magic and ruin my apartment,' Magnus explained weakly. He met Jace's eyes. 'I'm afraid you're going to have to find the Asag on your own.'

'You're not going to come with us?' Clary asked. 

Magnus shook his head. 'I need time to recover.' Magnus sighed tiredly. 'Besides...someone has to stay with Alexander.'

'How are we supposed to kill it?' Isabelle asked. 'You said our swords wouldn't work against the demon.'

'I said I didn't _know_ if they would work,' Magnus corrected. 'Between the three of you, you may be able to overwhelm it - Alec was able to slow it down on his own. The Asag is a demon, after all.' Magnus clutched his stomach, and coughed harshly, his chest heaving.

Isabelle started forward. 'Magnus, are you sure-'

Magnus waved a hand dismissively. 'Go! Go now, before we lose Alexander, and the Asag take more lives.'

Jace clenched his sword tightly and nodded. There wasn't any more they could do here. He looked up at the girls, and jerked his head towards the door. 'Come on.'

* * *

 

Jace was already trying to think of a strategy as they headed for the elevator in Magnus's apartment building. There was no doubt in his mind they needed to stop this demon tonight - Alec's life was at stake, and who knew how many mundanes this demon had killed while it had been here, or how many more lives it would take. Without Magnus to help, finding the demon would be difficult, but doable. Killing the demon, on the other hand, was going to be damn near impossible. Not the least because they didn't know how. 

Jace looked over at Clary. He noted the fear on her face, the set determination of her shoulders. He wanted to tell her to stay with Magnus, where it was safe, but he knew she wouldn't listen to him if he tried. That was something he loved about her - she was fierce in the face of danger, brave in the face of fear. She noticed him staring and he smiled reassuringly. Her face relaxed slightly, and she returned the smile. 

'Do you have a plan?' Isabelle asked quietly, breaking the silence in the elevator. Jace's eyes flicked to her. She was leaning against the wall of the elevator, a smirk on her face, and he knew she had probably been watching him watch Clary.

'We go to the Institute and collect the blood,' Jace said. 'Then we track the demon down and kill it.'

'Straightforward, simple,' Isabelle grinned. 'I like it.'

'Was it a good idea to leave Magnus alone like that?' Clary asked. 

'Magnus is a warlock,' Isabelle said. 'He's been around for hundreds of years. He'll be okay.'

'Still...' she sounded uncertain. 'Maybe one of us should have stayed.'

'He wouldn't have wanted us to.' Jace knew he spoke the truth - Alec's life was in their hands, and Magnus was trusting them to get the job done. 

Clary hesitated and then nodded in understanding.

'Jace...' Isabelle said slowly. Jace looked over to see she was looking at her phone, wide-eyed. She passed it to Jace and he saw the screen was lighting up with messages and alerts from the Institute and other Shadowhunters. One of them stood out to him, and he read it several times, just to be sure.

_Alert: extreme demonic activity detected at St Mary's Hospital, Brooklyn. Teams to make contact immediately for dispatch._

Jace looked up from the phone, smiling slightly. There was no way another demon was giving off that much power tonight. 'Looks like we found our demon.'

**Notes for the Chapter:**

> Hi friends! Thanks for being patient with me - my laptop was out of commission for a few days and I've been busy with work/uni, so I haven't had a lot of time to write. 
> 
> I really hope y'all are enjoying this fic. Let me know if you have any feedback in the comments below. There will likely be a few more chapters of this fic to come (not sure of the total yet) so I hope you can stick with me for a little while longer. Thanks for reading!
> 
> \- jaw xx


	8. Losing Battle

**Summary for the Chapter:**

> The end is nearing, and Alec is slipping.

_Alec was standing outside his bedroom door. He couldn't remember how he'd gotten there, but he somehow knew it was where he was supposed to be. He looked up and down the hallway, which seemed to stretch on forever in either direction. He reached out for the door handle in front of him and turned it, stepping through the doorway._

_He found himself in Magnus's apartment. The loft looked the same as it ever did, but instead of seeing the city view through the windows, all Alec could see was bright white light._ _He stepped further into the loft, and could see Magnus standing in front of one of the windows, looking out as though he could see beyond the light._ _Alec approached slowly, his footsteps echoing on the floor. He opened his mouth to ask Magnus what was going on, but nothing came out. He tried again, but his body wasn't responding to his commands._

_Magnus looked different when Alec reached him. His eyes were red-rimmed and his arms were wrapped around his chest, like he had to hold himself together. He didn't look Alec in the eyes, shying away from him._ _Alec wanted to reach out and take Magnus in his arms, but he didn't move, standing there like he was a stranger._

_Magnus sniffed and wiped his eyes with his thumb. 'What do you want?' Magnus asked, his voice rough. 'Haven't you done enough?'_

_Alec didn't understand. What had he done? Had he hurt Magnus?_ _Alec's mouth opened to speak. He wanted to ask Magnus what was going on, but the words that came out weren't his own. 'I'm not here for you. You have something I want.'_

_Magnus scoffed. 'Go away,' he muttered. 'I'm done with you.'_

_Alec was screaming inside his own head - why was Magnus saying this? This wasn't the man he loved. Alec wanted to tell him it was okay. Instead he moved to stand in front of Magnus, his silhouette casting a shadow over Magnus's face. Alec knew that this couldn't be real, even if it felt that way. He didn't want this to be real._

_Magnus hesitated, then reached out with his hands and tentatively held Alec's face between them, caressing his cheeks lightly with his thumbs. 'I wish things had ended differently between us,' Magnus whispered. He leaned in close and pressed his lips against Alec's. The kiss had such a sense of finality that Alec wanted to cry - but of course he didn't, his body refusing to respond._

_Magnus drew back slowly, letting out a shaky breath. Alec's hand reached out, and he thought he was about to embrace Magnus, but then his arm thrust forward in a powerful movement, ramming through something solid. Magnus jerked, and both of them looked down to see Alec's hand inside Magnus's chest. Alec realised he could feel his fingers closing around Magnus's heart._

_They stood like that for a moment, Magnus choking, his eyes wide and fearful and fixed on Alec with a look of such horror and betrayal that Alec would never be able to erase it from his mind. Alec wanted to scream, but all that came out of his mouth was huff as he withdrew his arm with a tug. Magnus crumpled to the ground. His empty eyes stared up at Alec as his life drained from the gaping hole in his chest._

_Alec shuddered and his skin tingled. He felt something lift from him - an energy of some kind, removing itself from his body - and suddenly he was in control again. He lifted his hand, staring down at the blood. It definitely felt real. He let a moan of panic, dropping to his knees beside Magnus's body. His hands reached out for Magnus's body, pulling at his clothes, leaving bloodstains on the floor and carpet and on Magnus's skin and-_

Oh god, what had he done?

_His chest was heaving with panicked sobs as he buried his face in Magnus's shoulder. He was dimly aware that the light_ _pouring through the windows was growing brighter, but he didn't care. He'd killed Magnus._

_He clutched at Magnus's body, holding it close, and Magnus's blood on his hands felt real._

This couldn't be real. 

_There was a bright flash all around him, and Magnus's body was suddenly gone, and Alec was holding nothing, his fingers clutching at air. He jerked back. He was still covered in blood and tears, but he was now in an empty white space, devoid of light, or furniture, or walls. There was nothing but white, stretching out before him eternally._

_Alec pressed the palm of his hand into his forehead, scrunching his eyes up. This wasn't real. He rocked back and forth on the ground, his brain catching up to the current influx of his emotions. Magnus wasn't dead. This was just another hallucination, another nightmare, another false reality. 'It's not real,' Alec mumbled to himself. He repeated the words, turning them into a mantra, a prayer. 'It's not real, it's not real, it's not real...'_

'You failed your friends,'  _a voice hissed around him. He jumped in surprise, looking around for the source, but there was nothing but white space._ 'You hurt them, you disappointed them. You're the reason they're going to die.'

_Alec shook his head. 'You're lying,' he said to the voice, not entirely sure he should be responding but at a loss of what else to do._

'Am I?'  _the voice questioned._  'Isn't Jace Wayland stronger without you? Isn't Isabelle Lightwood braver without you? Isn't Magnus Bane happier...without you?'

_'Stop it,' Alec mumbled. There was a part of him that agreed with the voice, a nagging thought at the back of his consciousness. Wouldn't they all be better off without him?_

'If you died, they'd be free,'  _the voice said._ 'You're only holding them back. You're useless. You're pathetic. You're weak.'

_The voice was growing louder and louder. Alec pressed his hands to his ears, trying to block out the sound, but it was in his head, too. He shouted, trying to drown out the voice with his own, but it was no use. It was too loud, it was everywhere, and he wasn't strong enough._

_It was right. He was useless._

_Alec curled into a ball on the ground, tucking his head close against his chest, sobbing quietly to himself as the voice around him reached a raging crescendo, screaming at him that he was nothing. He would never be more than nothing._

_He had finally figured out what was going on._

_This was his punishment._ _This was his hell._

* * *

 

Sirens were wailing loudly from St Mary's hospital across the road - someone had clearly pulled the fire alarm, though there was no sign of fire or even smoke. The building was being evacuated; patients, nurses and other staff were crowding in the parking lot and spreading out onto the street, and more were rushing through the hospital doors, being guided by security guards and police officers. 

Jace crossed the street, Isabelle and Clary hot on his heels, pushing through the crowd as quickly as he could. They needed to get inside and start searching for the Asag. Jace stopped when he reached the edge of crowd, close to the entrance. There were two cops on the door leading into the hospital foyer. He headed towards them, not entirely sure how he was going to get past them.

Jace tried to simply walk through the doors but one of the police officers threw his arm out, blocking him and the two girls behind him. Jace rolled his eyes - he should have known it wouldn't be that easy.

'Hey buddy, you can't go in there!' the cop said. 'The building's being evacuated! Turn around.'

'My brother's in there!' Jace said, whining a little to make it convincing. It wasn't his greatest plan but he couldn't think of anything else and they didn't have time to use their glamour runes. 

The police officer's face softened into a look of sympathy. He dropped his arm. 'I'm sorry, kid, but I can't let you-'

Jace sighed and made to turn away, then swung his fist hard, hitting the cop square in the jaw. The cop stumbled into a couple of doctors heading through the door and the crowd went down like a row of dominoes, one after the other. Jace stepped lightly over the mess of legs on the ground and sprinted across the foyer for the stairwell, ignoring the shouts from behind him. He threw a glance over his shoulder to make sure Isabelle and Clary were with him before hurrying up the stairs three at a time. 

'Did you have to hit him?' Clary panted from behind him.

'We made it inside, didn't we?' Jace shot back. He hoped the cops wouldn't enter the building to look for them, but it didn't seem like they were being followed.

The first floor doors flew open as they approached, and a couple of nurses hurried through, medical supplies in their arms. Jace and the others flattened themselves against the walls, and the nurses glanced at them as they passed. 

'You kids need to get out, now!' one of the nurses said without slowing down. She gave Jace a meaningful look as she and her colleague disappeared through the door below, but she didn't try to stop them. 

Jace ran up the last few stairs and stepped out onto the first floor. It was empty of people, the emergency lights glowing eerily, but there was no sign of the demon. 'Next one,' Jace said, turning back to the stairwell. 

They tried the second floor, which was the same as the first, and the third. By the fourth floor there was still no sign of the demon, and the hospital had been completely vacated of staff and patients. Jace was starting to wonder if he'd made a mistake, and the demon wasn't here at all, when they got to the fifth floor. 

It was darker than the others, the emergency lights flickering dimly. The air was cold and still, the darkness eerie. Jace looked up and down the corridor - he could see pieces of overturned hospital equipment and a couple of dark shapes on the ground.

The fire alarm was suddenly switched off with a loud click, and the silence was almost deafening. There no other sound to be heard, an odd thing for a hospital, and the lack of noise and proper light made Jace's skin crawl uneasily.

'Jace...' Isabelle murmured. He turned to see her crouching by something on the floor - a body. He swallowed dryly when he saw it was missing its head, the hospital gown it wore torn to the pieces and covered in blood. He knew in his gut they were in the right place. No human could have done that. 

Jace heard gagging behind him and turned to see Clary throwing up by one of the patient rooms. He went to her side and brushed her hair back from her face. 'You alright?' he asked gently. 

Clary straightened. 'Yeah,' she said, wiping her mouth. 'It's just...'

'I know.' Jace grimaced. 'Try not to think about it.' He knew it wasn't great advice, but he didn't know what else to say. 

'Where do you think it went?' Isabelle muttered. She'd moved away from the body, her staff glinting brightly in the dark. Jace drew his seraph blade and gestured with it down the corridor. The three of them headed into the dark, towards the nurse's station. The dark shapes on the floor were more bodies, some of them missing limbs, some of them almost unrecognisable as human beings. Jace tried not to look at them, afraid the guilt would make him break down. This was their fault. These people were dead because they'd pissed off a demon.

Jace stopped by the nurse's station. Two more hallways veered off, one continuing ahead and one to Jace's right. Isabelle moved straight ahead, but Jace was hesitant to split up. 'Maybe we should-'

A low growl emanated from the darkness ahead of them, cutting off Jace. Isabelle stopped in her tracks, her staff at the ready. Jace's eyes took a moment to focus in the dark, and then he saw it - a monstrous shadow, with a dozen green eyes and razor sharp teeth. 

'Shit,' Jace muttered. He swung his seraph blade, trying to calm the racing of his heart. 'I think we found our demon.' 

* * *

 

_Alec unfurled himself from the ball he'd curled into. The voice had stopped, and his ears were ringing in the silence. He looked up slowly. He was still in the white room, but he was no longer alone._

_Jace, Isabelle, Max and Magnus stood before him. They towered over him, staring down at him with shadowed eyes. Their skin was waxy and pale, and their clothes were in rags. The three of them lifted their left arms in unison, pointing down at Alec in judgement. The four of them spoke at the same time, their voices mixing strangely and echoing in the space around them._

_'Useless...weak...pathetic...nothing...'_

_They repeated the words, and started moving towards Alec. Alec scrambled to his feet and tried to run, but it was like he was caught in a dream, and no matter how hard he tried he couldn't move fast enough. The chanting was growing louder, and the frightening imitations of the people he loved most in the world were getting closer._

_Alec tripped on nothing, his foot dragging on the white space below him, and he fell with a grunt. The shouting quietened at the impact and he flipped onto his back to see the looming figures were fading, their forms turning opaque before disappearing altogether. Their chanting echoed around him, a remnant of their terrifying appearance, until it too faded into nothing._

_Alec took a few deep breaths, his heart racing, and then got to his feet again. He looked around him, wondering what would happen next, and was surprised to see a dark spot on the horizon. As he squinted, the shape grew bigger, and he realised it was moving towards him. With it came a humming presence - not a sound, but a feeling, something that made the air vibrate and the hair on Alec's neck stand on end._

_He backed away a few steps as the shadow rushed up on him. It morphed, forming a pillar and then moulding into the shape of a person. It stood a few feet away from him, it's face a swirling cloud of black smoke. It didn't have eyes, or any distinguishable features, but Alec's skin prickled like it was watching him._

_He raised a hand towards it tentatively, but jerked his arm back when the figure copied him. Alec tilted his head to the side and the figure did the same, and again when Alec tilted his head the other way. He stepped forward and figure mirrored that too, coming close to him._

_Curiosity won out over fear. 'What are you?' Alec asked._

_The figure's form rippled as it responded, as though it's voice was emanating from within it's shape. The sound came out fractured, like it was speaking through a radio on the wrong frequency. '...am...darkness.'_

_Alec frowned. There was something about the figure that made Alec squirm. He took a step backwards, but the figure followed him as he moved, maintaining the small space between them. 'I don't understand,' Alec said._

_The figure's form shook at his words and then it solidified, its smoke flicking downwards. Its surface turned shiny and black rather than smoke-like, and it now had distinctive features like a mouth. It reminded Alec of a manakin._

_The voice came out clearer this time. 'I am...your darkness.'_

_'What does that mean?' Alec whispered. His instincts were telling him to run, but he was afraid to look away, afraid to move in case the figure came after him. Besides, he didn't have anywhere to run to._

_The figure reached out a hand, independent of Alec's movement, and he tried to jerk back but the hand entered his chest before he could, in the same place where he'd put his own hand through Magnus's chest moments earlier. Alec felt something cold flood his system, ice water spreading from his heart throughout his body. The figure stepped closer to him, its arm plunging further into his chest. The figure turned back to smoke, flowing into him like a stream and pouring itself into his body through his chest._

_Alec dropped to his knees, the cold overpowering. He closed his eyes, falling forwards. He was expecting to hit the floor but it was as though he kept falling, hitting nothing, weightless and never-ending. The feeling of falling made his head spin with vertigo._

_The voice spoke again, inside his head._

I am your darkness. 

_Alec felt nothing, saw nothing, heard nothing. He was trapped in white, trapped in the empty. His mind curled in on itself. There nothing to hold, nothing grasp and pull, no lifeline to get him out of this, nothing to fight or breathe or see or think._

_The shadow inside him caressed him gently, lovingly, encouraging the nothing and the emptiness he was feeling. The presence inside him was pleased with his lack of resistance, with his free-fall into nothing._

I will be your end.

* * *

 

The room was still for a moment and then the demon let out a roar. It charged forwards on all fours, it's teeth flashing in the dark. Isabelle was closer to it than Jace and she stood her ground as the demon charged. The Asag swiped at her with a heavy paw, and Isabelle didn't have time to react as she was flung sideways into a wall.

'Izzy!' Jace yelled, watching helplessly as Isabelle fell to the floor with a thud, her staff clattering to the ground beside her. 

The demon ignored Isabelle and continued towards Jace and Clary. Jace grabbed Clary's arm and pulled her to the side, diving behind the nurse's station just in time. The Asag crashed into the nurse's desk, sending shards of wood and plaster flying everywhere. Jace was already moving around the other side of the desk, holding Clary's arm tightly. The Asag crashed through the nurse's station again, destroying the entire desk as it followed Jace and Clary down the hall. 

'To the stairs!' Jace shouted, frightfully aware the demon was right behind them, razor-sheep teeth only a few feet away. Clary made it through the doorway first, and Jace was about to leap through to join her when he felt shooting pain up his side. He faltered.

The pause was enough to allow the Asag to grab the back of his jacket with its clawed hand. Jace went sailing through the air, thrown by the Asag back down the hallway. His seraph sword was torn from his grasp, flying somewhere nearby with a clang. 

'Jace!' Clary called after him.

Jace hit the ground hard, sliding across the floor and coming to a stop down the other end of the ward, dazed. Pain lanced up his side, and Jace cried out at the intensity. Something was wrong. He pulled his shirt up and looked down to see his parabatai rune glowing red. Oh god - _Alec._

_'You should have run faster, boy.'_

Jace looked up through a haze of pain to see the Asag sauntering towards him, it's wide mouth open and panting. Jace tried to move back, but pain coursed through him again, and he clutched his side. He knew what the pain meant, and the emotional weight of it was worse than anything the demon could have done to him. Alec was dying, and Jace was feeling it happen.

_'I believe I am owed a meal,'_ the demon growled. It hovered over him, green eyes rampant with hunger and rage. The demon clamped its clawed hands around Jace's arms, pinning him to the floor. Jace let out an involuntary whimper as the rune on his side burned, his legs writhing. He was about to lose Alec for good. Maybe part of him was glad he was about to die too.

The demon opened it's mouth wider, teeth glistening, breath hot and stinking. Jace stared down the maw of the monster, and closed his eyes. His thoughts turned to Alec, trying to hold onto the bond they shared even as it slipped away. He reached out with his mind, with his heart, calling for his brother in the dark, but there was no response, only a presence drifting further out to sea. Alec's presence was being cut out of him, one thread at a time. 

Jace opened his eyes, steeling himself for the inevitable end. He wouldn't let this break him. Alec wouldn't want him to. Alec would want him to stare down death defiantly, like he always had. 

His father used to tell him that love was a weakness, but love would make him brave in death. Jace sneered up at the demon above him, watching as the Asag reared it's head back to strike...

And golden light exploded above him. 

**Notes for the Chapter:**

> Hey folks! Here's another chapter. I'm sorry it took so long to update, I'm going back to uni and have been very busy lately. Thanks so much for reading! I promise things get better soon. Let me know what you thought in the comments! 
> 
> Until next time - jaw xx.


	9. Fire and Brimstone

**Summary for the Chapter:**

> Jace and Clary fight the Asag; Magnus makes a rash decision.

Jace watched with amazement as light flared above him. It was as bright as the sun, and just as hot, illuminating the entire hospital floor. Heat emanated downwards, burning Jace's skin like he was standing too close to a radiator.

The Asag reared it's head back and screamed as the light touched it's back, and the strong smell of burning hair filled Jace's nostrils. He realised the light was burning the demon like acid, sizzling on it's skin. The demon's claws lifted from Jace's arms as it reared, and he scrambled to the side of the hallway, moving away from the demon's reach. The Asag dropped back to the ground, legs collapsing under it's weight as it's body was consumed by the rays of light. Jace crawled backwards, shielding his face as the light grew brighter, turning white. The brightness continued into a crescendo that Jace could see through his eyelids. Then there was a flash, and the heat and light was gone, the hospital ward was plunged back into darkness.

Jace opened his eyes to see the smouldering form of the Asag before him, unmoving and face down on the hospital floor. The demon's body was horribly burned, red flesh turned to blackened charcoal, it's back exposed to the bone. Jace used the wall to haul himself to his feet, the pain in his side burning sharply. He pulled his gaze away from the demon and saw Clary standing down the hall, her arm raised before her, a rune Jace didn't recognise shimmering on the palm of her hand. He realised with awe what she'd done - she'd used her gifts to make a new rune that would hurt the demon, and save his life, and she'd created something more powerful than he'd ever seen from a rune.

Clary lowered her arm, looking as surprised as Jace felt. After a pause she hurried towards him, stepping over the Asag's limbs and helping him back down the hall. The parabatai rune continued to burn at Jace's side, and he leaned heavily on Clary, gritting his teeth against the pain.

'Are you alright?' she asked. 

Jace shook his head. 'It's Alec,' he explained. 'Something's wrong.' He could see Isabelle on the ground close by, her dark hair covering her face. She was still out cold. He went to crouch by her, brushing her hair back from her face. There was a cut on her forehead, already raising into a lump. 

'Were we too late to help Alec?' Clary asked. 

Jace shook his head. He got to his feet with a groan. 'I don't know. We should get back to Magnus's...' He paused, looking back at the Asag's body. The demon wasn't turning to dust like it should be. He peered closer, and he inhaled sharply when he saw the demon move a little, it's leg jerking outwards.

It wasn't dead. 

'We gotta move,' Jace hissed. He grabbed Clary's arm and tugged her down the hallway, away from Isabelle, moving as quickly as he could. He could hear low growling behind them and the scraping of the Asag's claws on the tiled floor, and he ducked sideways, pulling Clary into a tiny storage cupboard. There was no light in here, and the room was pitched into darkness when Jace closed the door after them. He leaned back against the door, bracing himself against it with his legs. 

'Why are we hiding?' Clary whispered. 

'It's not dead,' Jace replied. Clary swore under her breath. Jace silently agreed - this thing was unstoppable. He listened intently for the Asag's approach, but he couldn't hear anything yet. 

'What's the plan?' Clary asked. 

Jace dug his fingers into his side, squeezing his parabatai rune. Alec was barely hanging on, and Jace. 'Can you use that rune again?'

'I don't know,' Clary whispered. She looked down at her palm. There was no sign the rune had ever existed, her palm clear, and Jace frowned. 'I could try,' she said. 'But I'd need a couple of seconds to get a good shot at it.'

There was a thudding noise. The demon was back on it's feet already, the wounds apparently not enough to slow it down.

'Okay.' Jace took a deep breath. 'I'll distract it,' he said quickly. 'Then you blast it. If it's not dead after that, I'm out of ideas.' He turned, fumbling for the door handle in the dark. 

'Wait, that's it?' Clary squeaked. 

'You got a better idea?' he asked her. 

There was a pause. 'No.'

'Didn't think so.'

He made to open the door again, then remembered something and reached out in the dark, to where he thought Clary was. She jumped when he touched her, his hand fumbling downwards in the dark for her leg. He found her sword's holster quickly and removed the seraph blade she carried, ignoring her noise of protest. 

'I'll need this more than you,' he said. He already felt better with the comforting weight of a sword in his hand. 'Ready?'

'Are you sure this will work?'

Jace smiled in the dark, even though he knew she couldn't see it. 'No. Don't take too long to draw that rune, okay?'

Clary scoffed quietly. 'You're crazy.'

'Only the right amount.' And with that, Jace threw the door open and stepped out into the path of the demon.

* * *

 

Magnus opened his eyes to find the ceiling spinning above him. He was lying on the sofa, but he didn't remember how he'd gotten there. He felt drained, his stomach churning and his body shaking. He could hear moans coming from somewhere nearby, as though someone was in pain. Magnus sat up slowly, pressing his palms into his eyes and rubbing hard. He remembered the events of the night vaguely - the summoning, the demon-spawn, Jace and the others heading to the hospital, and...

_Alec._

Magnus got to his feet quickly, swaying. There was no way for him to tell how long he'd been lying there, or how long Jace and the others had been gone. He had to get to Alec.

Magnus pushed down the nausea and managed to make it to the bedroom. Alec was still there on the bed, calling out weakly. It was only when Magnus approached the bed that he realised something had changed. 

Alec was no longer comatose; instead, his body was rigid, his back arching slightly off the bed, fists clenched at his sides. Magnus could see Alec's eyes rolling his head like he was dreaming. He knelt by the bed, placing his hand lightly on Alec's chest. Magnus could feel the tension in Alec's body the moment he made contact, like he was a bowstring poised for release, pulled taut and straining. 

'Alec?' Magnus said. Alec let out a soft moan at his name, and he jerked on the bed, his arm spasming outward as though he was reaching for something. 'Alexander!' Magnus said again, more forcefully. Alec responded again. He could hear Magnus, but whether he understood what Magnus was trying to say was another matter entirely.

Magnus took one of Alec's hands in his own, leaning in close to Alec's ear. 'You have to fight this, Alexander,' Magnus. 'You have to hold on, just a little longer.' Magnus wished he could do something more, but without magic there was nothing he could do. There was no wound, no injury to heal, no curse to lift. He felt useless, but he held on to Alec tightly, hoping that just by being there Alec would cling to life a little longer. 

'Fight this, Alexander!' Magnus said. 'I'm right here with you. I've got you. Fight it!'

Alec let out a whimper, and his body started to relax, the tension easing slowly. Magnus watched uncertainly - perhaps his words of comfort were working, and Alec was fighting back. But then Alec gasped, his eyes flying open and staring up towards the roof. Magnus jumped at the sudden movement. Alec turned to look at him and Magnus's stomach sank when he saw Alec's eyes were completely black, even the whites. Alec's mouth curled into a cruel grin, and Magnus's skin crawled at the sight.

_'He's gone, warlock,'_ Alec hissed, his voice gravelly.  _'He's not coming back.'_

Magnus's blood ran cold. 'Let him go,' he snarled at the creature speaking through Alec.

_'He screamed for you,'_ Alec taunted.  _'And I consumed him!'_

'No!' Magnus shouted. The creature using Alec's body laughed and threw his head back onto the bed. The laughter turned quickly into gasping breaths, and then with one final gasp for air, Alec's eyes fluttered closed. He slumped, his head lolling. Magnus shook Alec's arm, but the Shadowhunter was unresponsive. 

'Alec?'

Fear dropped into Magnus's stomach like a stone when he realised Alec wasn't breathing.  

* * *

 

Jace looked down the dark hallway and saw the Asag walking towards him slowly, a monster crawling out of the dark, limping as it walked. It was favouring it's back legs, the burns on it's back turning it's skin a mottled black and red. Jace felt a surge of satisfaction that the demon was hurt. It was about time the monster got what it deserved. 

He waited for the demon to focus on him, it's green eyes clouded with pain. 'Hey asshole! You want some of this?' he taunted, gesturing to himself. The beast roared weakly in response and picked up a little speed, charging towards him slowly, it's limbs dragging on the ground. Jace took a few steps back, and he caught sight of a doorway directly to his right. And idea quickly forming, he held his position, waiting for the demon to get close enough and praying to Raziel that this would work.

The demon was only a few feet away when Jace stepped aside, ducking swiftly into the doorway, the Asag's sharp claws missing him by a hair's breadth. He twisted around in the same movement and slashed at the demon as it passed him, slicing open a sizeable cut on the demon's side. The Asag bellowed loudly and skidded into the wall, crashing into the plaster and brick head first, green blood spattering onto the floor. 

Jace stepped back out from the doorway, his sword glistening with green. He smirked at the demon recovered from it's crash, pleased he'd managed to hurt it. He glanced behind him, hoping Clary would be ready to blast the damn thing while it was dazed. She was instead frowning at her palm, tracing a rune furiously with her stele. Nothing happened, so she tried again, shaking the stele furiously when it didn't work for a second time. 

Jace glanced back at the demon - it was picking itself back up, chunks of plaster flying across the hospital floor. It turned back towards him, it's dozen eyes blinking rapidly and out of synch. Jace hurried to Clary's side. 

'What's wrong?' he asked quickly. 

'It's not working!' she said. 'I remember it exactly, but...'

There was a roar, and the two of them looked back to see the Asag shaking it's head like a dog freeing itself over water. A dozen green eyes landed on the two of them, and the Asag screamed viciously.

'Move!' Jace shouted, grabbing Clary's hand. They sprinted up the hall, back towards the nurse's station. Jace's heart was in his throat - he could practically feel the Asag's hot breath on the back of his neck. The pair of them reached the t-intersection, and in a split-second decision, Jace flung himself sideways around the corner, pressing his back into the wall and pulling Clary with him. The Asag thundered by, driven by pain and rage and moving too quickly to stop suddenly. It used it's clawed arms out and grabbed the walls, it's claws digging into the plaster. The demon whirled, but it didn't charge them again, instead fixing them with an angry stare and stalking slowly towards them, intent on turning them into a meal. 

Jace placed Clary behind him, the seraph blade before him. He knew facing the demon with just a sword was stupid, and it would be an impossible feat to defeat it like this, but they were out of options. Jace gave Clary a soft smile, intent on memorising the details of her face before the end came for them. She looked back at him with fear in her eyes, and he felt a stab of guilt. It was his fault she was in the middle of this in the first place. 

The demon stood before them, tail waving agitatedly like a cat's. The cut in it's side was already healing, the flesh nearly sealed back together. Jace could see no visible sign of the burns inflicted only a few moments earlier. They had been fighting a losing battle from the beginning.

_'You will pay for what you have done!'_ the demon growled, it's voice low and vengeful. 

Jace stepped forward determinedly, the sword raised. He would see this to the bitter end. 'So will you,' he said, the words sounding braver than he felt. 

The Asag lunged, teeth flashing, and Jace would have responded in kind, but as he raised the sword higher, the pain in his side reached a peak, and he fell to his knees, drawn inside himself as Alec's dying soul called out to him across the void.

* * *

 

'No...'

Magnus was already on his feet. He checked Alec's pulse at his neck, but there was no beat under his fingertips. He placed his hands over Alec's chest, the words of a revival spell already on his lips, when he remembered - _he didn't have magic._ Frustration and fear made his heart ache painfully, and he scrunched his hands into Alec's shirt. 

'No!'

He stood for a few seconds, his body shaking with adrenaline, then he rearranged his hands, placing them in the centre of Alec's chest. The mundane form of resuscitation was something he had learned many years ago, but he assumed the technique was roughly the same. He took a deep breath and pushed down, completing a round of compressions, mimicking the movements he'd seen countless of times before in movies, TV dramas, and real life on one occasion. 

He got to the breaths: tilt the head, pinch the nose,  _breathe._ Repeat. 

He continued with the movements, ignoring the tears that had started to stream down his face. _Don't be dead, don't be dead, don't be dead,_ _please, don't be dead!_

On his fourth repetition, Alec gasped slightly when Magnus moved his mouth away, and the warm glow of relief flooded Magnus's system like a shot of whiskey. 'That's it, Alexander!' Magnus panted, dropping to his knees beside the bed. He reached out and stroked Alec's face, smiling at the sight of Alec's chest rising and falling again. 'Breathe, my love.'

Alec coughed, breathing raggedly. He mumbled something under his breath that Magnus couldn't make out, and then passed out again.

Magnus let out a shaking sigh. Alec was breathing, and his heart was beating, and Magnus had bought him some time. But how long did he have left? Magnus collapsed onto the floor, running a hand through his hair, his hands shaking from the adrenaline. He shook his hands, trying to ease some of the pent up energy his body had given him, and reached up and placed his fingers on Alec's wrist, feeling for the pulse. It was there, but faint and slow. He kept his fingers in place, the heartbeat seemingly counting down the seconds he had left like a doomsday clock.

He couldn't do this on his own, not without his magic, only there wasn't enough time to bring anyone else into this. Alec could be gone again by the time anyone arrived. But the more Magnus thought about it, the more he knew that magic was his only option, but it was the one option he couldn't access. Potions, portals, healing...there was nothing he could do as he was. Perhaps this was what the Asag had intended all along - leave Alec trapped, with nothing to help him and no way out.  

Magnus could feel the panic in his throat, the fear tightening inside his chest like a vice. He sat there for a few minutes, staring at the bookshelf opposite him but not really seeing it, pushing his tired brain to the limit to think of a solution. His eyes focused on the bookshelf, and he read the cover of the book he was staring at - _Magic Amongst Men and Monsters._ It had been a gift from Ragnor Fell, something the warlock had stolen from a faerie...

Magnus's mind clicked. He'd been slow, blinded by emotion and fatigue, and he could have punched himself. He should have thought of it earlier.

_The fey._

Magnus rushed to the chest of drawers by his bed, pulling the bottom one out completely and throwing it aside, clothes spilling out of the drawer and onto the floor. He ignored the mess, reaching into the space where the drawer had been. His hand scrabbled around for a few moments before he pulled out a small object wrapped in glossy material and tied by twine. He unwrapped the material carefully, and in his hands he held a tiny glass bottle, filled with a glowing, pink substance. 

Years earlier, when he'd first arrived in New York, there had been an incident with one of the fey. He'd saved a young faerie from a demon in one of the downtown pubs, and the Queen had offered him a gift in return.

_'Use this,'_ the Queen had said,  _'when you are at your lowest in life.'_

Magnus had assumed she'd meant emotionally, until he'd tried the potion some years ago, on a day when he'd been depressed and lonely. It was a magical supplement, something that boosted his magic for a few seconds, giving him enough power to nearly destroy his apartment.  

The feeling of untamed magic had been exhilarating, and that had just been with one drop. The only catch - the side effects had left him bedridden for days afterwards. 

Magnus looked over at Alec, at his pale, prone form on the bed, and his heart hardened. There wasn't a choice here. He would do whatever it took to save Alec. 

Magnus screwed the top off the glass bottle. There were still several more drops of the potion left, but he would need more than a few seconds to try and save Alec. He took a breath, and then tipped his head back and swallowed the rest of the pink liquid in one gulp. 

* * *

 

Time moved in slow motion around Jace. Alec was calling for him across the void, and he was drawn under, following the thread that connected him to Alec. He was still aware of the demon before him, but he didn't care. Alec was dying, and Jace could feel the strings connecting them being cut, one by one, piece by piece. 

The pain was excruciating. 

The Asag was getting closer, teeth gnashing, eyes glowing. Clary was at his side, screaming for him to move, but he couldn't. He was rooted in place, the crushing void before him holding him still. Alec was going to be lost to him forever, but it was more than that. Jace hadn't been able to stop it. 

There was movement before him - a person was leaping onto the remains of the nurse's station, standing tall beside the demon, and Jace recognised the black hair and the steel staff - Isabelle. She leapt onto the Asag and the force of her jump knocked the creature down, the demon crashing into the wall with a cry of frustration. 

Jace jerked when another thread was severed, the last few connecting him to Alec. He could feel nothing but distance between them now. This was it. This was the end. His heart was being torn in two, and there was nothing he could do to stop it. He closed his eyes against the tidal wave crashing around him, the suffocating weight of nothing pulling the very air out of his lungs.

Distantly, he could hear squelching sounds, grunts and kicks, and he opened his eyes to see the Asag lying on it's side, breathing heavily, a spear through it's middle. Isabelle appeared before him, hair wild, blood dripping down her forehead from the cut on her head, and she took his face in her hands. She knew, and she felt his pain. 

'It's okay, Jace,' she said, her voice echoing in his ears. The darkness was consuming him, crushing him. Alec was almost gone. 

'What's happening?' Clary's voice burst through the bubble around him. Isabelle didn't answer, holding Jace upright. He reached the end, the final thread, the last piece of Alec that was connected to him, and the scissors were poised to cut it. The terror of life without Alec expanded before him like a balloon, the rubber edges about to burst, and he held his breath, the end so close... 

And then something incredible happened.

The thread didn't break. Instead, it grew back, tangling back into Jace's soul, fragile but still existing, and he breathed again. He breathed like he'd never breathed in his life. The darkness receded, and time resumed it's normal pace. The pain in his side receded into a throbbing.

Jace smiled softly. He should have given Alec more credit. 

Isabelle frowned. 'Jace?' she whispered. 

He shook his head at her. 'Not yet,' he replied, and her eyes widened. Whether it was with surprise or worry, Jace didn't know. He wasn't sure he knew himself, but it was a miracle. Alec was holding on.

Jace lifted his gaze to look behind her. The demon was struggling for the staff in it's side, wriggling it's claw to try and pull the staff free. It's eyes were trained on the three of them like it was staring at it's first meal in days. Jace reached out for Clary's hand, he pressed the stele she still held against his palm. He knew now, somehow, that this was what he was meant to do. This would be enough to kill the demon.  

'Draw the rune on me,' Jace said firmly, his eyes fixed on the demon. The Asag was breathing hard, blood dripping from the wounds in it's sides. Jace wondered what it was waiting for. 

Clary paused for a fraction of a second, her eyes round and huge, and then she did as he asked, tracing the rune onto Jace's palm quickly. Jace closed his hand into a fist and rose to his feet, The demon lunged weakly, dragging it's wounded body across the floor, it's skin scraping the ground, blood smearing across the tiles. 

'It's time you paid for what you've done,' Jace snarled. He raised his arm towards the demon, unfurling his fingers.

Golden light erupted from his palm. 

**Notes for the Chapter:**

> Hey folks! I'm so sorry it's been so long, but I just haven't had time to write and edit. It's week one of my last year at uni, I've had some health problems going on and it's been really hard to find time for this. Anyway, here we are! I hope you guys are still enjoying the story.
> 
> I also want to say I'm not particularly happy with this chapter, but I wanted to give you guys something at least half decent so that's what this ended up being. It's a little longer too, so hopefully that makes up for my lateness. 
> 
> I will try to update again as soon as I can, but I can't say when that will be as life is pretty crazy right now. Hopefully it will be soon because I already know what I want to do for the next chapter, but I'm not making any promises. 
> 
> Thanks so much for reading. If you have any feedback leave me a comment below! I love hearing from y'all.
> 
> \- jaw xx


	10. Death Becomes You

**Summary for the Chapter:**

> Alec is hanging on by a thread. Magnus takes drastic measures to save the man he loves.

_The darkness greeted him gently, embracing him like an old friend. He sank into the touch, lost in the blank empty. He could no longer feel his own body, and he no longer cared why that was. He was a ship floating out at sea, the last candle flickering in a dark room._

_His chest fluttered, his heart giving way to the throes of death, his lungs pulling at the air for their last breaths. Everything felt so far away, like this was all happening to someone else, someone he wasn't. The pain and fear was gone, and all he felt was exhaustion._

_He would have accepted sleep, accepted the darkness, if he hadn't heard the voice. It was faint, reverberating softly in the deep recesses of his mind, but he heard it._

'Fight!'

_He pushed the thought away. He didn't want to fight anymore. He was poised to fall into the abyss, and he didn't want to try and stop it. His free-fall was coming to an end, the ground hurrying to meet him, and he was almost glad he would crash into it. Put himself out of his misery. Strangely, the thought of dying didn't frighten him as it once had. And yet, he clung to life, almost as though he wasn't ready to let go._

_He didn't want to fight anymore. He just wanted this to be over._

* * *

 

The potion's effects were almost instantaneous. Power surged through Magnus's veins like water breaking through a dam. He threw his head back, inhaling deeply. His entire being was thrumming with energy, magic radiating outward from his body in spikes of static, flooding the room with a blue haze that splintered the walls and rattled the furniture.

He had never felt better.

Magnus lifted his hand and flexed. A pulse of energy burst outwards, shaking the chest of drawers before him and cracking the wooden floorboards. He made the same movement again, holding it longer, pushing more magic into it. The chest of drawers split, the wood breaking into jagged pieces, his belongings spilling onto the floor. Magnus grinned and climbed smoothly to his feet. He felt invincible, untouchable, like he wasn't just a conduit anymore, but made of magic. It was criminal this kind of potion was not more commonly manufactured or offered to his kind. The things warlocks would be able to do with this kind of power at their disposal were endless. 

Magnus moved his arm slowly, mesmerised by the way the air seemed to bend around him, a shroud of blue encircling his body. He was intoxicated, his body buzzing with power. The things he could do like this, the monsters he could defeat - Magnus had never considered himself to be one for revolution, but with power like this, he could conquer the world. He could already see it, burning through demons and Downworlders alike, the other warlocks kneeling at his feet, the fey willing to do his every bidding, the vampires and werewolves his soldiers in an army of monsters...

Something pulled his gaze downward and he saw Alec's body on the bed, his chest barely moving, and Magnus remembered why he'd done this in the first place. A rush of fear and love surged through him, and he shoved the thoughts of power and prestige aside and climbed onto the bed, laying on his back beside Alec. The magic oozed out of him as he moved, surrounding the two of them in a cloud of blue. Magnus reached out and took Alec's hand, cold fingers worryingly unresponsive to his touch, and he closed his eyes.

Through the physical contact, Magnus poured his mind into Alec's body. He didn't need words of power to perform spells anymore - he simply  _pushed_ , the magic rushing out of him and into Alec. He was acting on instinct, feeling. He pushed until he found the darkness that had once been Alexander, the creature smothering Alec's soul. Magnus could feel evil before him, and he was horrified when he saw there was barely any of Alec left, his life-force eaten away by darkness.

Magnus was enraged. The man he loved was in pieces, broken by a creature who knew nothing more than to follow it's master's orders, to feed on light until there was nothing left.

Magnus reached out with a clawed fist of magic and dug it into the darkness like a grappling hook, and then he tugged, pulling the shadow away from Alec's consciousness. He felt a glow of pleasure as the energy sizzled at the creature's essence, burning away some of the darkness. 

The creature retaliated in kind, sending waves of dark energy back at him, attempting to smother his power, but Magnus barely felt the return attack, shielding himself with a wall of energy. The darkness bounced off him, and he shot spikes of magic at the creature instead. He clawed and scratched at the creature with everything he had, turning his emotions into weapons and digging deep until he started to see the shadow fall away, the light buried underneath now revealed to him. 

The dark creature flinched under the assault, and Magnus drove his magic further, stabbing at the creature relentlessly, chipping away at the roots it had buried in Alec's mind. He could feel the essence of the creature slipping, failing, falling apart, and he only pushed harder in response. 

 _Let him go_ _!_ Magnus shouted inside his mind, putting as much authority as he could behind the command. Slowly but surely, Magnus was winning. He was beating the creature down, he could feel the darkness lifting from Alec's mind - 

Alec's consciousness suddenly flickered, the light dimming and almost disappearing. Magnus distantly felt the bed jerk as Alec jolted, his body responding to the assault on his mind, and he immediately pulled back his onslaught. The creature was losing yes, but it's hold on Alec was deep.

Magnus inspected the bonds tying the creature to Alec, and realised the creature had dug in so far that it was practically symbiotic, sustaining Alec as Alec sustained it, eager to get every last drop of life from Alec's soul. 

To kill the creature would be to kill Alec. 

Magnus withdrew his attack, too frightened to continue, but unwilling to leave yet. Frustration churned in his stomach - he had come so far, only to have this opportunity ripped away in an instant. He was stuck between a rock and a hard place - an impossible choice he didn't want to face, and couldn't make.

And just like that, inches from victory, Magnus had lost.

* * *

 

_Something was holding him back from death. Wrathful energy. It was permeating his brain, bleeding into the dark recesses where he hid from the pain and the fear. It was so much stronger than he remembered reality to be. Almost too much for him to bear._

_The energy burned with hatred and fear and passion and love, all emotions he no longer recognised in himself. He wanted to ignore it, desperate to simply slip away, tired of the torture. The turmoil emanating from the blue light too much for him to bear, and it would be so much easier if it just let him go._

_But it was calling for him._

_He lifted his head and saw the blue tendrils of energy above him, breaking the darkness apart like lightning. The longer he looked at the shards of blue, the more they reminded him of someone. There was a person he'd forgotten, a name that had been lost in the sea of dark surrounding him. Someone important._

_He strained, reaching for the name, even though a part of him told him not to, told him to simply let it go and continue his fall. It was a name taken from him not by choice, but by force, a name that had once meant so much to him but had been so easily forgotten._

_When he recalled it, everything changed. He no longer felt the weight pressing down on him. The blue energy grew brighter, veins trailing across the sky in a spider's web, the darkness no longer oppressive but suppressed, peeling back and exposing raw flesh underneath. Maybe dying wasn't such a good idea after all, because now he had a memory to live for._

_Magnus was coming for him._

* * *

 

The darkness was waiting expectantly for Magnus to make another move, but however much Magnus wanted to destroy it, he couldn't. Not without hurting Alec. He pulled back, trying to think of a way out of this, but all he could come up with were dead ends. All the while, the shadow grew in strength, the realisation that Magnus was no longer trying to kill it letting it form again. The darkness expanded hesitantly, approaching him cautiously. He could feel it's lust across the psychic plane - the shadow _wanted_ him, wanted the life he held within himself, the memories and years he had a rich source of energy for it to feed on. Compared to Alec, Magnus was an oasis, a haven with an endless supply of power.

The creature was already feeding on Alec again, bleeding back into the parts of Alec Magnus had just freed, and it was leering for him at the same time, desperate for sustenance. Magnus did the only thing he could think of. He pleaded for surrender.

The concept formed as a suggestion in his mind, and he sent the idea across to the creature. He was given confusion and hunger in return, so Magnus formed words in the hopes the creature would understand.  

 _Take me instead._ The creature paused in it's actions, the feeding process freezing, and Magnus knew he had it's attention.

 _Take me, and let him go,_ Magnus said. The creature retracted, unwilling to give up it's current victim when it still had life left in it. Magnus desperately tried to pull it's interest back towards him, distinctly aware of how close Alec was to dying. He pushed magic towards the creature, but this time, it wasn't an attack. It was a gift. The creature swirled towards him, tasting the magic and power, and he felt it's lust in response. It wanted more. 

 _I have so much to offer you,_ Magnus continued. His heart was pounding a million miles a minute, and the magic inside him was screaming for release, for revenge, for domination, but he didn't waver. Self-preservation be damned, taking this creature into himself was the only way to save Alec. And unlike Alec, Magnus could fight back.

He had no intention of going down easily.

 _There's so much life in me for you to feed on,_  Magnus said, urging the creature to take the bait, teasing with more magic. _Take me, and leave him._

The creature paused, and Magnus was worried it wouldn't agree, but then it extricated itself slowly from Alec's mind. Shadows oozed out of Alec's consciousness, forming into a shadow creature that swirled before Magnus. Magnus waited until all of the darkness was free, and Alec's mind was glowing on it's own, unhindered by darkness and growing stronger every minute. Once he was sure Alec was safe, he drew back into himself, and opened his eyes.

* * *

 

_Alec could see light - bright blue energy he now knew belonged to Magnus. Magnus had found him. Magnus was saving him. Magnus was bringing him home._

_His body shuddered as the darkness pulled away, leeching out of him like fluid draining from a wound. Gradually, sensation was returning to him. He could feel the bed beneath him, the soft surface against his back, the aching of his body. He could hear the thumping of his heart, loud in his ears. The sound was more comforting than anything else he'd ever heard in his life._ _He was alive, rushing towards the light of a day like he was strapped to the front of a bullet train._

_Magnus had saved him._

_He was free._

* * *

 

Magnus looked to his left through the blue haze of magic. Alec was still, but he was breathing, his face pinched into a frown. Alec stiffened as Magnus watched. His mouth flew open and a cloud of black smoke rushed out of him, hovering above the bed like a cartoon raincloud. Alec relaxed, breathing deeply and without effort, the pinched expression fading into one of peace. Magnus let out a breath himself, the relief tangible in his belly, solid and warm - Alec was safe.

He'd done it. 

Magnus turned his attention to the demon floating above him, the cloud shifting and bubbling towards him. It seemed excited to enter it's new home, eager to see the promised reservoirs of memories and power. 

Magnus had no intention of letting the demon get that far. 

He lifted a hand, reaching out towards it enticingly, and the creature seemed to think the movement was an invitation. It blew towards him, funnelling into a dark shadow. Magnus smiled at the approach, and then flicked his hand quickly. 

Magic burst out of his palm in a shaft of blue light, hot and spitting. The light pierced straight through the middle of the creature, blasting it into smaller pieces of black smoke, and the creature emitted a wailing noise of surprise.

Magnus gritted his teeth and pushed harder, lifting his back off the bed to get closer, the blue magic getting hotter and hotter and blistering his palm painfully. He widened the beam and it spread to encompass all of the creature, hissing every time it burned away some of the black shadow. 

The creature's screams grew higher in pitch, piercing Magnus's eardrums painfully, but he didn't stop. He shouted, the beam of energy brightening, the blue bathing the entire room in it's glow.

Magnus was satisfied he'd held on for long enough after a minute or so, and he cut off the energy, breathing hard. The demon cloud was nowhere to be seen. Grey dust scattered on the bed and floor around him, settling over the wrecked room in a thin coat. Magnus had scorched the ceiling, and most of his furniture was in splinters from the force of the magic, but he smiled anyway. 

Finally, the creature was dead.

Magnus stared down at his hands - he didn't feel at all drained of magic, the power still boiling in his veins like molten lava, his entire being buzzing with adrenaline and _victory_. He could do anything he wanted with this power, kill any demon.

And then his heart jolted, and Magnus remembered why he'd hidden the potion away.

It was like someone had pulled a plug. The magic drained out of him, all at once, pouring out into the air around him in a blue vapour. Magnus could feel his heart thundering in his chest, his head bursting with unbearable heat and pain.

It was over in only a few seconds, but it felt like a lifetime of torture. He collapsed back onto the bed, his heart hammering into his ribcage, his head feeling like it would explode. He couldn't fight the darkness as it pulled him under like an anchor at sea, sinking into unconsciousness. 

Out of the corner of his eye, Magnus saw Alec stir beside him. 

* * *

 

Alec inhaled deeply. He could smell burning, the taste of something metallic upon his tongue.

He opened his eyes and blinked. He was staring up at a destroyed ceiling, the plaster completely burned away, the wooden beams underneath exposed and burned. Alec frowned and turned his head, taking in his surroundings. The room looked familiar under all the destruction - he was in Magnus's bedroom.

The sight of it made him feel an odd mixture of sadness and happiness. The room was destroyed, but he was back. He was free.

Alec looked to his right and realised he was lying on Magnus's bed. More importantly, he was lying next to Magnus, and he smiled. It felt like weeks since he'd seen Magnus, the real him, and Alec reached out to touch Magnus's hand which lay next to his own on the bed.

His smile quickly faded when he saw the trail of blood leaking from Magnus's nose.

 

**Notes for the Chapter:**

> Hey fam! Thank you all so much for 1200 hits!! I'm more appreciative than words can say that people are reading my writing! Thank you, from the bottom of my heart :D
> 
> Let me know what you thought about this chapter in the comments! Thanks for reading, and I'll try to update soon - jaw xx
> 
> P.S. Y'all excited for S3?


	11. Dust to Dust

**Summary for the Chapter:**

> The demon finally gets what it deserves.

Fire poured from the rune on Jace’s hand in an impossible display of angelic magic. He grasped his wrist with his other hand, trying to keep his arm steady. He took a step back, pushing against the force of the angel fire, desperately holding his position. 

The Asag screamed, the inferno hitting it head on. Jace couldn't see the damage he was inflicting, the light too bright to look at, but he could hear the screaming, and the sizzling of flesh. The light grew brighter, hotter, and Jace could feel his skin blistering. He held his position, shouting with the effort, holding on by a thread. This was for Alec, and all the chaos this demon had wrought.  

There was a flash, and Jace shut his eyes to avoid being blinded. He felt a wave of heat wash over him, and then the power blooming from his hand shut off like someone had flicked a switch. Jace stumbled backwards, surprised by the sudden loss of resistance, and someone caught him, hands pressing into his back.

'Are you alright?' Clary asked from behind him. Jace turned to see her watching him with concern, her hair flyaway, her cheeks flushed red from the heat.

'By the Angel,' he breathed. He stared down at his hands in awe. The rune shimmered on his palm before disappearing without a trace, leaving behind red and blistering skin. 'That was...incredible.' He let out a little laugh of uncertainty, his heart pounding in his chest. 

Clary gave him a small smile, then her eyes flicked over his shoulder and widened in horror. Jace followed her gaze, and saw Isabelle was staring in the same direction, her mouth set in a hard line. 

'Damn,' Isabelle muttered. 

Jace could have screamed in frustration. The hallway was ruined, the walls charred and black, windows shattered into pieces. Green blood stained the ground, splattered around the hall, and the distinct smell of burned hair hung in the air.

There was no other sign of the demon itself, not even a pile of dust. 

'What the hell is it going to take to kill this thing?'

* * *

 

Alec could feel his heart pounding dangerously fast in his chest. He shook Magnus gently, and Magnus let out a low moan in response, but he didn't open his eyes. The blood was trailing down across Magnus's cheek, drawing a dark red line across his face. Alec wiped the blood away with a shaking hand. 

Fear was digging a pit in his stomach, and he couldn't help but wonder if this was just another hallucination. Maybe he was still stuck in that hell, and all of this was just an illusion.

But Magnus had saved him...hadn't he?

There was a snapping sound from above, and Alec looked up to see the wooden beams of the ceiling splintering, sagging inwards. His heart sank. The ceiling was damaged, and above it was the roof of the building - and who knew how many feet of concrete, bricks, and insulation. Hallucination or not, they needed to move. 

Alec rolled over and pulled himself to his feet, his chest aching at the movement, his head spinning once he stood upright. He moved as quickly as he could to the other side of the bed. He didn't have the strength to lift Magnus completely, so Alec wrapped his arms around Magnus's chest from behind and dragged him off the bed. Magnus's chin drooped onto his chest, and his feet snagged on the debris on the ground as Alec pulled him. 

With every step it got harder for Alec to breath. He was certain he had bruised, perhaps even broken ribs, though he wasn't sure how that had happened. He intended to get a full report on what had happened since he'd blacked out once they were out of this mess.

The ceiling squealed loudly and Alec tried to move faster, grunting with the effort of exertion. Magnus was unresponsive in his arms, completely unaware of the danger they were in. 

They made it to the doorway just in time. Magnus's legs had just cleared the threshold when the roof finally gave way with a deafening crash; wood, plaster and brick tumbled inwards, crushing what remained of Magnus's furniture. Alec fell back in surprise, Magnus landing half on top of him.

A dust cloud burst outwards from the wreckage, billowing towards them. Alec coughed, squeezing his eyes shut and trying to cover his and Magnus's mouth and nose.

Eventually the dust settled, forming a thick layer on every surface and clogging the air. Alec was covered in the stuff, and he looked at Magnus to see his clothes and hair had turned grey. But the sight of the dust wasn't what caused Alec's blood to run cold. 

A second trail of blood had joined the first, slowly trickling from Magnus's nose and over his lips.

* * *

 

'Spread out. It can't have gone far in that state.'

Jace did as Isabelle instructed. The demon was injured, he was sure of it - nothing could have survived the angel fire unscathed. He was hopeful that their angelic blades would be enough to send the Asag back to Edom now that it was weakened. Jace was determined for this to end. Now.

Jace headed down the hallway before him, the two girls splitting off and going down the other two corridors. His boots crunched over the burned floor, crushing pieces of glass and charred floor tile. The ward was eerily silent. Jace could hear every hammer of his heart behind his ribs. 

There was a soft sound from his right, and Jace turned quickly, his blade held out before him. He could have sworn he saw a puff of red smoke out of the corner of his eye, but when he looked, the room was empty. 

'Izzy...' Jace called softly, his eyes searching the darkness carefully. He heard her reply from one of the other corridors, the sound of her footsteps approaching him quickly.

'What is it?' she asked when she reached him, staring into the dark room like he was. 

'I thought I saw it,' Jace said. He turned at the sound of footsteps to see Clary approaching them, walking quickly down the corridor. His heart leapt when red smoke materialised above her head. 

'Clary, duck!' Jace shouted, running towards her. She dove forward without hesitation, hitting the ground and spinning to look behind her.  

The demon solidified above her and crashed to the ruined floor. It was back in it's human form, it's clothes in tatters, smoke rising slowly off it's seared flesh. Jace ran forward and helped Clary to her feet, pulling her back from the demon. The demon lifted it's head and snarled at him, and Jace's stomach twisted when he saw what was left of the Asag.

Half of it's flesh had melted, exposing red muscle and bone underneath. The demon's face had been burned away, and there was nothing left but eyes, teeth and the tendons of it's jaw. Green blood oozed from it's face like pus from a wound. 

The demon opened it's deformed mouth, words bubbling out of it's gullet. 'Shadowhunters,' the demon snarled. 'You will... _pay_...for what you have done.'

The demon staggered to it's feet and disappeared again in a red flash, reappearing a few feet closer to them. It lurched forward like a zombie, snarling and gurgling as it moved, hands curled into claws.

With another puff of smoke, it teleported behind them, letting out an inhuman screech. Jace and the others whirled, seraph blades at the ready. The demon screamed at them before lunging, arms swinging wildly. Jace danced out of the way, but the demon rounded on him. With another flash of red the demon reappeared at his side. The Asag lunged at him, it's teeth sinking deep into the flesh of his shoulder. Jace shouted with the pain, scrabbling at the monster latched onto him. 

There was a crack, and the Asag was thrown off him and pulled across the corridor, hitting the opposite wall. Jace clutched the bite on his arm, watching as Isabelle unfurled her whip from around the demon's middle.

The demon roared, and pulled off the wall, heading for Isabelle. Jace was certain it would have torn her to pieces had a blade not appeared in it's chest. 

The Asag jerked and let out a surprised grunt, and looked down to see a pointed seraph blade protruding from it's chest. The blade was withdrawn with a hideous squelch, and the demon clutched at the hole in it's chest, dropping to it's knees. Clary stood behind the Asag, her seraph blade dripping with green ichor. She glared down at the demon, and Jace felt pride surge in his chest.

The demon heaved on the ground, air whistling through it's exposed teeth with every ragged breath. It's jaw flexed, and Jace realised it was trying to smile. It looked up at them, the alien grin on it's phase more creepy than menacing. 'You cannot kill me...I am... _immortal_...'

'You don't look very immortal to me,' Isabelle replied. She cracked her whip threateningly, and the demon's cockiness disappeared.

'Shadowhunters...' the demon gurgled. 'You will all... _die..._ for what you have done...'

Jace approached the demon, his fingers tightening around his seraph blade, his injured arm pressed tightly to his side. The demon looked up at him with a mixture of pain and hatred, it's mutilated face trembling as it spoke.  

'You kill me...your friend dies...' the demon growled. 

For a moment, Jace was afraid. What if the demon was telling the truth - what if Alec died when the demon did? 

But he could tell in his gut that the demon was lying. 

The demon was watching for his reaction with narrowed eyes, it's tongue hanging over it's teeth in anticipation. Jace weighed his seraph blade in his hand, tossing the sword by the handle.

'You're a liar,' Jace said calmly. 'And I'm done with you.'

He gripped the sword tightly, and in a swift, practiced movement, he sliced the blade out in front of him, cutting cleanly through the Asag's neck. The Asag choked, and then it's body collapsed, it's head thudding to the floor beside it's corpse. 

'Enjoy your ride back to hell,' Isabelle said, a touch of amusement in her voice.

Jace watched with satisfaction as the bloody mess before him disintegrated into dust.

* * *

 

Alec climbed to his feet and pulled Magnus backwards, dragging him clear of the dust and out into the apartment's main room, where the air was reasonably clearer. He laid Magnus on a rug, placing a pillow under his head, and wiped away the blood with his sleeve. 

'Magnus?' Alec croaked out. He tapped the side of Magnus's face gently with his hand, but the warlock didn't respond to the touch any more than he had before. Alec's bottom lip quivered - he could feel tears burning in the corners of his eyes, and he blinked them away. Now was not the time to panic. Magnus was still alive, and Alec had to find a way to save him. 

Alec forced himself to take a deep breath. _Plan...plan...think of a plan!_

He needed help.

The apartment was empty, and he had no idea how long they had been alone or where the others could be. First thing was to call the others.

Alec looked around for a phone, and saw Magnus's cell sitting on the coffee table by the sofas. He grabbed it and swiped it open, ignoring the messages on the lock screen, and dialled Isabelle's number.

He got her voicemail and cursed. He tried Jace's number next, and Jace answered on the third ring. 

'Magnus, is Alec alright? We managed to kill the demon-'

Alec inhaled sharply at the sound of Jace's voice. 'It's me.'

There was a pause, and Alec could feel the distant rush of emotions from his parabatai - worry, anger, exhaustion. But when Jace finally spoke, all Alec heard was relief. 'Oh, thank Raziel. You're okay.'

Alec nodded. He stared down at Magnus, his vision blurring, and he clutched the mobile like his life depended on it. 'Jace...I need help.'

'I'm on my way.'

**Notes for the Chapter:**

> Hey friends, here's another (late) update for you all! Sorry it's been so long, I've been busy with uni work and I got sick over the weekend. 
> 
> I hope you enjoyed it, and thank you so much for reading! I'm so happy to see all your comments and kudos, I appreciate it so much and it keeps me going :3
> 
> Probably won't be too many more updates after this one, we're near the end of the road! 
> 
> Until next time - j.a.w. xx


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